1. Caramelize the Onions

1. Heat olive oil in a skillet over medium-low heat.
2. Add onions and cook 20–25 minutes, stirring often, until soft and deeply golden.
3. Season lightly with salt and set aside.

2. Cook the Mushrooms

1. In the same skillet, add mushrooms and cook 6–8 minutes until the moisture evaporates.
2. Add garlic, thyme, salt, and pepper; cook 30 seconds until fragrant.
3. Combine the mushrooms with caramelized onions and let them cool slightly.

3. Prepare the Phyllo Crust

1. Preheat oven to 375°F (190°C).
2. Brush a tart pan (9–10 inch) with butter.
3. Lay one sheet of phyllo in the pan, brushing lightly with butter.
4. Repeat with remaining sheets, rotating slightly and letting edges overhang.

4. Assemble

1. Spread the onion-mushroom mixture evenly over the phyllo base.
2. Whisk eggs and cream, then stir in grated cheese.
3. Pour custard evenly over the filling.
4. Fold or trim excess phyllo edges.

5. Bake

• Bake 30–35 minutes, until filling is set and phyllo is golden and crisp.

6. Serve

• Rest 10 minutes before slicing.
• Serve warm or at room temperature.