Baked Brie with Caramelized Onions

Ingredients

Ingredient notes & substitutions

Brie cheese:

Look for a quality 8 oz wheel with a soft, creamy interior. Bring it to room temperature before baking so it warms through evenly. Camembert is the best substitute if you can't find brie.

Yellow onions:

Yellow onions have the perfect balance of natural sugars for caramelizing. Vidalia or sweet onions work too and turn even sweeter. Slice thin and even so they cook uniformly.

Butter + olive oil:

The combination gives you the flavor of butter with the higher smoke point of oil — perfect for the long slow cook without burning.

Brown sugar:

Just a teaspoon helps the onions caramelize faster and deeper. Skip only if you want to keep it strictly savory; honey or maple syrup work as swaps.

Fresh thyme:

Its floral, slightly lemony notes pair beautifully with sweet onions and creamy brie. Dried thyme works in a pinch — use 1/3 teaspoon since it's more concentrated.

Method

1. 1

   Preheat the oven to 350°F (175°C) and line a small baking sheet or oven-safe skillet with parchment paper.

2. 2

   Heat the butter and olive oil in a large skillet over medium-low heat. Add the sliced onions and stir to coat.

3. 3

   Cook the onions low and slow for 25 to 30 minutes, stirring occasionally so they don't burn — they should turn soft, golden, and jammy.

4. 4

   About halfway through, sprinkle in the brown sugar, thyme, salt, and pepper. Continue cooking until deeply caramelized.

5. 5

   While the onions cook, place the brie wheel on the prepared baking sheet.

   
6. 6

   When the onions are ready, pile them generously on top of the brie, mounding them so the cheese is completely covered.

7. 7

   Bake for 12 to 15 minutes, until the brie is warm and gooey but still holds its shape (not fully melted into a puddle).

8. 8

   Garnish with extra fresh thyme leaves and serve immediately with toasted baguette slices for dipping and spreading.

   

Variations to try

• Add a spoonful of fig jam or apricot preserves on top of the onions for an extra sweet-savory layer.
• Wrap the whole thing in puff pastry before baking for a golden, flaky shell.
• Add balsamic vinegar (1 tablespoon) to the onions while cooking for a tangier, more complex flavor.
• Top with toasted walnuts or pecans for crunch alongside the sweet onions.

Storage & make-ahead

Best served warm, right out of the oven — the brie firms up quickly as it cools. If you have leftovers, store in an airtight container in the fridge for up to 3 days. Reheat gently in a 300°F oven for 5 to 8 minutes until soft and warm again; microwave works too but be careful not to overheat, which turns brie oily. Leftover caramelized onions are gold — spread them on burgers, pizzas, sandwiches, or grilled cheese.

Frequently asked questions

Can I use store-bought caramelized onions?

Yes — skip the caramelizing step and warm the store-bought onions gently in a pan before piling on the brie. Homemade tastes better, but store-bought is a real time-saver.

How do I know when the brie is done?

You want it warm and gooey when pressed, but still holding its shape from the outside — usually 12 to 15 minutes at 350°F. Any longer and it turns into a puddle.

Can I make this ahead?

Absolutely. Caramelize the onions and pile them onto the brie up to a day ahead — cover and refrigerate. Bake fresh right before serving so the cheese is warm and gooey.

What can I serve besides baguette?

Crackers, sliced apples or pears, toasted pita chips, or fig-and-olive crackers all work beautifully. A fruit-and-cracker board around the brie is a classic move.