These Mini French Onion & Gruyère Puff Pastry Cups take everything you love about classic French onion soup – slow-caramelized onions, nutty Gruyère, and rich savory depth – and tuck it into buttery, golden puff pastry. They’re elegant enough for holiday gatherings but easy enough for weeknight entertaining. Make the onions ahead, assemble quickly, and watch them disappear the moment they hit the table.

If Thanksgiving feels overwhelming, I made a simple guide that walks you through the whole week.

Mini French Onion & Gruyère Puff Pastry Cups

Ingredients for the caramelized onions:

• 3 large yellow onions, thinly sliced

• 2 tbsp butter

• 1 tbsp olive oil

• 1/2 tsp salt

• 1 tsp sugar (optional, accelerates caramelization)

• 1–2 tsp balsamic vinegar or 1 tbsp sherry (optional for depth)

• Fresh thyme (a few sprigs)

Ingredients for assembly:

• 1 sheet puff pastry, thawed

• 1 – 1 1/4 cups shredded Gruyère cheese
  (or 1 cup Gruyère + 1/2 cup mozzarella for extra melt)

• Fresh thyme leaves, for topping

• Flaky sea salt (optional)

Directions:

1. Heat butter and olive oil in a skillet over medium heat. Add onions, salt, and sugar (if using). Cook for 25–35 minutes, stirring often, until deep golden. Add balsamic or sherry and thyme; cook 2 more minutes. Remove from heat and let cool. (Chef note: Deep, dark onions are KEY for both flavor and visuals – don’t rush them.)
2. Preheat the oven to 400°F. Lightly spray a mini muffin tin. Unroll the puff pastry on a lightly floured surface. Cut into 2 to 2.5-inch squares (about 24 per sheet). Press each square gently into a mini muffin cup, letting the corners stand up.
3. Add 1–2 teaspoons of caramelized onion to each cup. Top with a small pinch of Gruyère (about 1 tablespoon). Add a leaf or two of fresh thyme on top.
4. Bake for 12–15 minutes, or until the pastry is puffed, the edges are deep golden, and the cheese is bubbling and lightly browned.
5. Let cool for 5 minutes to help the cups set. Add a tiny sprinkle of flaky salt. Optional: drizzle with a touch of warm balsamic glaze for shine. Serve warm or at room temperature on a platter with fresh thyme sprigs.

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If you want a calmer, more organized Thanksgiving this year, I created a full Thanksgiving Guide with a seven day plan, make ahead recipes, and hosting tips.

Check out some other fall recipes!

Hi I’m Teresa!

I’m a mom to three, a wife and a physician assistant. I also have a degree in Nutritional Sciences and I love sharing all things life with you! I am passionate about empowering you through education, sharing all my fave products and items that have made life better and creating content to give you value!