French Onion Soup Empanadas

Preheat oven to 375°F (190°C). Line a baking sheet with parchment paper.

Heat butter and olive oil in a large skillet over medium heat. Add onions and cook, stirring occasionally, until deeply caramelized, about 20-25 minutes. Reduce heat if needed to prevent burning.

Add garlic and thyme to the skillet and cook for 1 minute more.

Pour in beef broth (or vegetable broth) and sherry (if using). Add bay leaf. Bring to a simmer and cook until the liquid has reduced slightly, about 5 minutes. Remove bay leaf and season with salt and pepper to taste.

Remove from heat and let cool slightly.

In a small bowl, whisk together the egg and water for the egg wash.

Place a spoonful of the onion mixture in the center of each empanada disc. Top with a generous pinch of Gruyere and Emmentaler cheese.

Moisten the edges of the empanada disc with a little water. Fold the disc in half, forming a half-moon shape. Press the edges firmly to seal, and then crimp with a fork to ensure a tight seal.

Place the empanadas on the prepared baking sheet. Brush the tops with egg wash.

Bake for 20-25 minutes, or until golden brown.

Let cool slightly before serving.