Apple, Cheddar & Caramelized Onion Flatbread

Quick Recipe Version (TL;DR)

Yield: 4 servings (1 large or 2 smaller flatbreads)
Prep Time: 20 minutes
Cook Time: 35–40 minutes
Total Time: 55–60 minutes

Quick Ingredients

2 large yellow onions, thinly sliced
2 tbsp unsalted butter
1 tbsp olive oil (plus 1 tbsp for brushing dough)
1/2 tsp fine sea salt, divided
1 tsp sugar (optional, for onions)
1 tsp balsamic vinegar (optional, for onions)
1 lb pizza dough (store-bought or homemade), room temperature
1 large crisp apple (Honeycrisp, Pink Lady, or Granny Smith), very thinly sliced
6 oz sharp cheddar cheese, shredded (about 1 1/2 cups packed)
1 tsp fresh thyme leaves (or 1/2 tsp dried), plus extra for garnish
1/4 tsp freshly ground black pepper
Flaky sea salt and honey, optional for serving

Do This

1. Preheat oven to 450°F (232°C) with a pizza stone or inverted baking sheet inside.
2. Caramelize onions in butter and oil with salt (and sugar if using) over medium-low heat, 25–30 minutes; finish with balsamic.
3. Stretch room-temperature dough into a large oval or two smaller rounds; place on parchment.
4. Brush dough lightly with olive oil; scatter half the cheese, then spread caramelized onions on top.
5. Layer thin apple slices over onions; sprinkle remaining cheese, thyme, salt, and pepper.
6. Slide parchment and flatbread onto hot stone or pan; bake 10–14 minutes until golden and bubbly.
7. Cool 3–5 minutes; finish with extra thyme and a light drizzle of honey if desired. Slice and serve warm.

Why You’ll Love This Recipe

Perfect balance of sweet apples, deeply savory caramelized onions, and sharp cheddar.
Uses simple, everyday ingredients but feels special enough for entertaining.
Flexible base: use store-bought pizza dough to keep it easy, or your favorite homemade version.
Works as a cozy weeknight dinner, elegant appetizer, or festive party snack.

Grocery List

Produce: Yellow onions, 1 large crisp apple, fresh thyme (optional but recommended).
Dairy: Unsalted butter, sharp cheddar cheese.
Pantry: Pizza dough, olive oil, fine sea salt, flaky sea salt (optional), black pepper, sugar (optional), balsamic vinegar (optional), honey (optional).

Full Ingredients

For the Caramelized Onions

2 large yellow onions, thinly sliced (about 4 cups sliced)
2 tbsp unsalted butter
1 tbsp olive oil
1/2 tsp fine sea salt
1 tsp sugar (optional, helps speed up caramelization)
1 tsp balsamic vinegar (optional, for depth and color)

For the Flatbread

1 lb pizza dough, at room temperature for at least 30 minutes
1 tbsp olive oil, for brushing the dough
6 oz sharp cheddar cheese, shredded (about 1 1/2 cups packed; white or orange is fine)
1 large crisp apple (such as Honeycrisp, Pink Lady, or Granny Smith), cored and very thinly sliced
1 tsp fresh thyme leaves, plus extra for garnish (or 1/2 tsp dried thyme)
1/4 tsp freshly ground black pepper
Pinch of fine sea salt, to taste

Optional Finishes

Flaky sea salt, for sprinkling just before serving
1–2 tsp honey, lightly drizzled over the hot flatbread

Step-by-Step Instructions

Step 1: Preheat the Oven and Prepare Your Equipment

Place a pizza stone or an inverted, heavy baking sheet on the middle rack of your oven. Preheat to 450°F (232°C) for at least 20–30 minutes so the stone or pan gets very hot. This high, even heat is what gives you a nicely crisped flatbread base.

While the oven heats, line a large baking sheet or your countertop with a sheet of parchment paper. You will build the flatbread on the parchment so it can be easily transferred to the hot stone or pan.

Step 2: Caramelize the Onions Slowly

In a large, wide skillet, heat 2 tbsp butter and 1 tbsp olive oil over medium heat until the butter is melted and just starting to foam. Add the sliced onions and 1/2 tsp fine sea salt. Stir to coat the onions evenly in the fat.

Cook the onions over medium-low heat, stirring every few minutes. After about 10 minutes, if you like, sprinkle in 1 tsp sugar to encourage browning. Continue to cook, stirring regularly and adjusting the heat to prevent burning, until the onions are a deep golden brown and very soft, about 25–30 minutes.

When they are nicely caramelized, stir in 1 tsp balsamic vinegar (if using) to deglaze the pan and pick up any browned bits. Taste and adjust salt if needed. Remove from heat and set aside to cool slightly.

Step 3: Prep and Stretch the Dough

While the onions are finishing, make sure your pizza dough has been at room temperature for at least 30 minutes; cold dough is hard to stretch and will keep springing back. Lightly flour your hands and, if needed, the parchment paper.

Place the dough on the parchment and gently press it out into a large oval or rectangle, about 12–14 inches long and 1/4 inch thick. You can also divide the dough into two pieces and make two smaller flatbreads for easier handling or serving. Try to keep the edges slightly thicker to create a natural crust that will hold the toppings.

Step 4: Slice the Apple and Prep the Toppings

Core the apple and slice it very thinly (about 1/8 inch thick). Thin slices cook quickly and soften just enough while still holding their shape. A sharp knife or mandoline works best.

Shred the cheddar cheese if it is not already shredded, and pick the leaves from a few sprigs of fresh thyme (if using). Having everything prepped and ready makes assembly fast once you start.

Step 5: Assemble the Flatbread

Brush the surface of the stretched dough lightly but evenly with 1 tbsp olive oil, leaving a small border around the edges. This is your “sauce” and will help the crust crisp while adding flavor.

Sprinkle about half of the shredded cheddar over the oiled dough. Spoon the caramelized onions over the cheese, spreading them out evenly.

Arrange the apple slices in slightly overlapping rows or shingled circles over the onions. Distribute the remaining cheddar evenly on top. Finish with 1 tsp fresh thyme leaves, 1/4 tsp black pepper, and a small pinch of fine sea salt.

Step 6: Bake Until Golden and Bubbling

Carefully slide the parchment with the assembled flatbread onto the preheated pizza stone or inverted baking sheet in the oven.

Bake at 450°F (232°C) for 10–14 minutes, until the crust is golden brown on the bottom and edges, the cheese is melted and bubbly, and the apples look just tender and lightly golden at the tips. If you divided the dough into two smaller flatbreads, start checking around 9–10 minutes.

Step 7: Finish, Slice, and Serve

Using oven mitts, carefully slide the parchment and flatbread back onto a baking sheet or cutting board. Let it rest for 3–5 minutes so the cheese sets slightly and it is easier to slice.

Sprinkle with a pinch of flaky sea salt and a few extra thyme leaves. For a subtle sweet finish, drizzle with 1–2 tsp honey while still warm (this complements the sharp cheddar beautifully). Slice into wedges or squares and serve warm.

Pro Tips

Take your time with the onions. Truly caramelized onions should be soft, jammy, and deep golden—not just lightly browned. If they start to burn, lower the heat and add a splash of water to the pan.
Thin apple slices are key. Thicker slices will stay too crunchy and can weigh down the flatbread. Aim for 1/8-inch slices or thinner.
Use room-temperature dough. Cold dough shrinks and resists stretching. If it springs back a lot, let it rest for 5–10 minutes, then try again.
Get the oven really hot. Preheating the stone or pan thoroughly is what gives you a pleasantly crisp bottom crust instead of a soggy one.
Shred your own cheese if possible. Pre-shredded cheese often contains anti-caking agents that can make it melt less smoothly.

Variations

Apple, Cheddar & Bacon Flatbread: Add 4–6 slices of cooked, crumbled bacon over the caramelized onions before adding the apples and remaining cheese.
Apple & Blue Cheese Twist: Replace half of the cheddar with crumbled blue cheese for a more intense, tangy flavor. Drizzle with honey to balance the sharpness.
Herbed Whole-Wheat Base: Use a whole-wheat or multigrain pizza dough and sprinkle a little extra dried thyme or rosemary into the dough before stretching for a more rustic feel.

Storage & Make-Ahead

The flatbread is best enjoyed fresh from the oven, but leftovers can be stored in an airtight container in the refrigerator for up to 3 days. Reheat slices on a baking sheet in a 375°F (190°C) oven for 8–10 minutes, or until the crust is crisp and the cheese is hot and melty.

You can make the caramelized onions up to 3 days in advance. Store them in a covered container in the fridge, then bring to room temperature or gently rewarm before assembling the flatbread. The dough can also be prepped in advance if using a homemade recipe that allows for cold fermentation in the fridge.

Nutrition (per serving)

Approximate values per serving (1/4 of the flatbread): about 525 calories, 25 g fat, 55 g carbohydrates, 4 g fiber, 20 g protein, 900 mg sodium. Exact numbers will vary based on the specific dough, cheese, and add-ins used.