Quick Recipe Version (TL;DR)
Quick Ingredients
- 1 cup unsalted butter, softened (divided: 1/2 cup for cakes, 1/2 cup for filling)
- 1/2 cup vegetable shortening (for filling)
- 1 cup packed light brown sugar; 1/2 cup granulated sugar
- 2 large eggs; 4 tsp pure vanilla extract (divided)
- 1/2 cup buttermilk; 1/2 cup whole milk
- 2 cups all-purpose flour; 1 1/2 cups quick-cooking oats
- 1 1/2 tsp baking powder; 1 tsp baking soda; 3/4 tsp salt
- 1 1/2 tsp ground cinnamon; 1/4 tsp ground nutmeg
- 2 1/2 cups powdered sugar
- 1 jar (7 oz) marshmallow creme
- 2–3 tbsp heavy cream or milk (to thin filling, as needed)
Do This
- 1. Preheat oven to 350°F (175°C). Line 2 large baking sheets with parchment paper.
- 2. Cream 1 cup butter with brown and granulated sugars until fluffy. Beat in eggs and 2 tsp vanilla.
- 3. Whisk flour, oats, baking powder, baking soda, salt, cinnamon, and nutmeg. Add dry ingredients to wet, alternating with buttermilk and milk, until just combined.
- 4. Scoop 1 1/2-tablespoon mounds onto sheets, spacing 2 inches apart. Bake 10–12 minutes, until set and lightly golden. Cool completely.
- 5. For filling, beat 1/2 cup butter with shortening until smooth. Add powdered sugar, marshmallow creme, 2 tsp vanilla, pinch of salt, and enough cream for a fluffy, spreadable texture.
- 6. Match cakes in pairs by size. Pipe or spread filling onto the flat side of one cake and gently sandwich with its partner.
- 7. Chill assembled whoopie pies 20–30 minutes to set the filling, then serve slightly cool or at room temperature.
Why You’ll Love This Recipe
- Soft, pillowy oatmeal cakes warmly spiced with cinnamon and nutmeg for a cozy, old-fashioned feel.
- A fluffy vanilla marshmallow cream filling that tastes like classic Amish bakery whoopie pies.
- Perfect make-ahead treat for potlucks, lunchboxes, bake sales, and holidays.
- Easy, homey recipe with simple pantry staples and clear, step-by-step instructions.
Grocery List
- Produce: None required (optional: fresh flowers or herbs for styling when serving)
- Dairy: Unsalted butter, eggs, buttermilk, whole milk, heavy cream (or extra milk)
- Pantry: Vegetable shortening, quick-cooking oats, all-purpose flour, light brown sugar, granulated sugar, powdered sugar, marshmallow creme, pure vanilla extract, baking powder, baking soda, fine salt, ground cinnamon, ground nutmeg, parchment paper
Full Ingredients
Spiced Oatmeal Cakes
- 1 cup (2 sticks / 226 g) unsalted butter, softened
- 1 cup (200 g) packed light brown sugar
- 1/2 cup (100 g) granulated sugar
- 2 large eggs, at room temperature
- 2 tsp pure vanilla extract
- 1/2 cup (120 ml) buttermilk, at room temperature
- 1/2 cup (120 ml) whole milk, at room temperature
- 2 cups (250 g) all-purpose flour, spooned and leveled
- 1 1/2 cups (135 g) quick-cooking oats (not instant)
- 1 1/2 tsp baking powder
- 1 tsp baking soda
- 3/4 tsp fine sea salt (or table salt)
- 1 1/2 tsp ground cinnamon
- 1/4 tsp ground nutmeg
Fluffy Vanilla Cream Filling
- 1/2 cup (1 stick / 113 g) unsalted butter, softened
- 1/2 cup (95 g) vegetable shortening, at room temperature
- 2 1/2 cups (300 g) powdered sugar, sifted
- 1 jar (7 oz / 200 g) marshmallow creme (marshmallow fluff)
- 2 tsp pure vanilla extract
- Pinch fine salt (about 1/8 tsp)
- 2–3 tbsp heavy cream or whole milk, as needed for consistency
Optional Garnish
- 2–3 tbsp extra quick oats, for sprinkling on the tops before baking
- Light dusting of powdered sugar, for serving
Step-by-Step Instructions
Step 1: Prepare your pans and preheat the oven
Preheat your oven to 350°F (175°C). Line 2 large baking sheets with parchment paper. This helps the soft oatmeal cakes release cleanly and keeps their bottoms tender rather than overly browned.
Measure out all your ingredients before you begin mixing. Make sure the butter, eggs, buttermilk, and milk are at room temperature so they blend smoothly and create a fluffy, even batter.
Step 2: Cream butter and sugars
In a large mixing bowl (or the bowl of a stand mixer fitted with the paddle attachment), add the softened butter, brown sugar, and granulated sugar. Beat on medium-high speed for 3–4 minutes, scraping down the sides of the bowl once or twice, until the mixture is very light and fluffy. This step adds air, which helps keep the oatmeal cakes soft and cake-like.
Add the eggs one at a time, beating well after each addition until fully incorporated. Mix in 2 tsp vanilla extract. The mixture should look smooth and slightly thick.
Step 3: Combine dry ingredients and finish the batter
In a separate medium bowl, whisk together the flour, quick-cooking oats, baking powder, baking soda, salt, cinnamon, and nutmeg until everything is evenly distributed and there are no clumps of leavening or spices.
With the mixer on low speed, add about one-third of the dry mixture to the creamed butter mixture, followed by half of the buttermilk and half of the whole milk. Mix just until combined, then repeat with another third of the dry ingredients and the remaining buttermilk and milk. Add the final third of the dry ingredients and mix on low until no dry streaks remain. Do not overmix; stop as soon as everything looks evenly moistened.
The batter will be thick but scoopable, with visible oat flecks throughout.
Step 4: Scoop and bake the oatmeal cakes
Using a small cookie scoop or tablespoon, drop rounded mounds of batter onto the prepared baking sheets, using about 1 1/2 tablespoons of batter per cake. Space them at least 2 inches apart; they will spread slightly in the oven. Aim for 32 cakes total so you can make 16 whoopie pies.
If you like, lightly sprinkle a few extra oats on top of each mound for a rustic look.
Bake one sheet at a time for 10–12 minutes, rotating the pan halfway through, until the cakes are puffed, set at the edges, and the tops spring back lightly when touched. They should be only lightly golden around the edges, not dark brown.
Step 5: Cool completely before filling
Let the oatmeal cakes cool on the baking sheet for 5 minutes, then carefully transfer them to a wire rack to cool completely. Because the texture is soft and cake-like, moving them while hot may cause them to break, so be gentle.
Allow them to cool for at least 30 minutes. If the cakes are even slightly warm when you add the filling, the filling can melt and slide out.
Step 6: Make the fluffy vanilla cream filling
While the cakes cool, prepare the filling. In a medium bowl, beat together the softened butter and vegetable shortening on medium-high speed for 2–3 minutes until smooth, creamy, and slightly lighter in color.
Add the sifted powdered sugar, marshmallow creme, vanilla, and a pinch of salt. Start mixing on low speed so the sugar does not puff out of the bowl, then gradually increase to medium-high. Beat for 3–4 minutes, until the mixture is very light, fluffy, and holds soft peaks.
Add 2 tablespoons of heavy cream or milk and beat again. If the filling seems too thick, add up to 1 additional tablespoon cream or milk, a little at a time, until it is airy, smooth, and easily spreadable but not runny.
Step 7: Assemble the Amish oatmeal whoopie pies
Once the oatmeal cakes are completely cool, sort them into pairs of similar size and shape. Place one cake from each pair flat-side up on a work surface.
Transfer the filling to a piping bag fitted with a round tip (or simply use a spoon or offset spatula). Pipe or spread a generous layer of filling (about 2 tablespoons) onto the flat side of each bottom cake, leaving a small border around the edge.
Gently press the flat side of the matching top cake onto the filling, twisting slightly to spread the filling to the edges without squeezing it out. Repeat with all pairs.
For the best texture, place the assembled whoopie pies in a single layer on a tray, cover loosely, and chill in the refrigerator for 20–30 minutes to let the filling firm up and the flavors meld before serving.
Pro Tips
- Use quick oats, not old-fashioned. Quick-cooking oats give the cakes a tender, uniform texture. Old-fashioned oats will make them chewier and may cause uneven spreading.
- Do not overbake. These are meant to be soft and cake-like. Take them out as soon as the tops are set and spring back lightly; overbaking will make them dry.
- Match sizes for tidy sandwiches. Take a minute to pair up similar-sized cakes before filling so your whoopie pies look neat and stack easily.
- Adjust filling thickness. If the filling feels loose, add a little more powdered sugar. If it is too stiff, beat in tiny splashes of cream or milk until it is fluffy and spreadable.
- Chill for clean edges. A brief chill after assembly helps the filling set, making the pies easier to transport, stack, and slice in half for sharing.
Variations
- Raisin oatmeal whoopie pies: Fold 1/2 cup plump raisins into the finished batter before scooping for an even more old-fashioned, cozy flavor.
- Maple-vanilla filling: Replace 1 tablespoon of the cream with pure maple syrup and add 1/2 teaspoon maple extract for a maple twist that pairs beautifully with the spiced oats.
- Cream cheese filling: For a tangier filling, replace half the shortening with 4 oz softened cream cheese and increase powdered sugar by 1/2 cup to keep the texture thick and pipeable.
Storage & Make-Ahead
Store assembled Amish oatmeal whoopie pies in an airtight container, in a single layer or separated by parchment paper, in the refrigerator for up to 5 days. Let them sit at room temperature for 15–20 minutes before serving so the cakes soften slightly.
For short-term storage (up to 2 days), they can be kept at cool room temperature if your kitchen is not too warm, though refrigeration keeps the filling more stable.
To freeze, place unfilled oatmeal cakes in a single layer on a baking sheet and freeze until solid. Transfer to a freezer bag or container and freeze for up to 2 months. Thaw at room temperature, then fill as directed. You can also freeze fully assembled whoopie pies: wrap each individually, then place in a freezer-safe container for up to 1 month. Thaw overnight in the refrigerator.
Nutrition (per serving)
Approximate values per whoopie pie (1 of 16): about 480 calories, 24 g fat, 13 g saturated fat, 65 g carbohydrates, 2 g fiber, 43 g sugar, 5 g protein, and 280 mg sodium. Actual values will vary based on exact ingredient brands and portion sizes.
