Whenever I make these treats, the house is filled with an amazing aroma that everyone enjoys!

1 pre-made tart crust or 1 cup crushed crackers mixed with 1/4 cup melted butter
3 large onions, thinly sliced
2 tablespoons olive oil
1 tablespoon butter
1 teaspoon sugar
1/2 teaspoon salt
1/4 teaspoon black pepper
1 cup shredded Gruyère cheese
1/2 cup heavy cream
2 large eggs
1 teaspoon fresh thyme leaves (optional)

Preheat your oven to 375°F (190°C).

If using a pre-made tart crust, place it in a tart pan. If making a crust from crushed crackers, mix the crackers with melted butter and press into the bottom of a tart pan to form an even layer.

In a large skillet, heat olive oil and butter over medium heat. Add the sliced onions and cook, stirring occasionally, until they begin to soften, about 10 minutes.

Sprinkle the onions with sugar, salt, and pepper. Continue to cook, stirring frequently, until the onions are deeply caramelized, about 20-25 minutes. Remove from heat and let cool slightly.

In a bowl, whisk together the heavy cream and eggs until well combined.

Spread the caramelized onions evenly over the prepared crust.

Pour the cream and egg mixture over the onions, then sprinkle the shredded Gruyère cheese on top.

Bake in the preheated oven for 25-30 minutes, or until the cheese is melted and golden brown, and the filling is set.

Remove from oven and let cool slightly before slicing. Garnish with fresh thyme leaves if desired.

For a different flavor profile, try using goat cheese or feta instead of Gruyère. You can also add sliced mushrooms or roasted red peppers to the caramelized onions for additional depth. If you prefer a gluten-free option, use a gluten-free cracker crust or a base made from almond flour. For a touch of heat, sprinkle a pinch of red pepper flakes over the cheese before baking.