In a large skillet over medium heat, add the olive oil. Once heated, toss in the sliced onions, seasoning them lightly with salt and pepper. Stir occasionally for about 15-20 minutes or until they’re golden brown and soft.

Once your onions are caramelized, take them off the heat. In a large bowl, combine the ricotta, mozzarella, Parmesan, thyme, and the caramelized onions. Mix well.

Preheat your oven to 375°F (190°C). Lay one sheet of phyllo dough on a clean surface and brush lightly with melted butter or spray with cooking spray. Layer another sheet on top. Repeat for a total of four sheets.

Cut the layered dough into 4 vertically and 4 horizontally, creating 16 squares.

Place a spoonful of the cheese and onion filling in the center of each square. Gather the corners of the dough around the filling, pinching to create a parcel. Place them seam-side down on a baking sheet.

Brush the tops with more melted butter and bake for 15-20 minutes, or until golden and crispy.

Allow them to cool slightly before serving. Best enjoyed warm but still delicious at room temperature!