Caramelized Onion and Gruyere Tartlets

Slow caramelized onions do all the heavy lifting here: no tomatoes needed for richness, just patience and butter. These are the savory bite that makes guests ask for the recipe, so consider this your advance copy.

Makes 24 tartlets · 1 hour

Ingredients

• 2 sheets puff pastry, thawed
• 3 large yellow onions, thinly sliced
• 3 tablespoons butter
• 1 teaspoon fresh thyme leaves, plus more for garnish
• 1 1/2 cups grated gruyere
• Salt and black pepper

Instructions

1. Melt the butter in a large skillet over medium-low heat. Add the onions and a pinch of salt; cook low and slow 30 to 35 minutes, stirring occasionally, until deeply golden and jammy. Stir in the thyme.
2. Heat the oven to 400°F. Cut the puff pastry into 24 squares and press each into a mini muffin tin.
3. Fill each shell with a spoonful of onions and a generous pinch of gruyere.
4. Bake 15 to 18 minutes, until puffed and bubbling. Garnish with thyme and serve warm.