Caramelized Onion & Mushroom Pastry
A speedy take on rogal świętomarciński—crispy puff pastry swirls filled with deeply caramelized onions, sautéed mushrooms, and melted cheese. Ready in 20 minutes and perfect for dinner.
- Total time
- 20 min
- Servings
- 4
- Calories
- 385
- Protein
- 11g
Ingredients
- 1 sheet (thawed) frozen puff pastry sheet
- 2 whole yellow onion, large
- 8 oz mushrooms (cremini or button), sliced
- ¾ cup gruyère or sharp cheddar, shredded
- 1 tsp thyme (fresh or dried)
- 1 whole egg yolk
- ½ tsp caraway seeds (optional, traditional)
Instructions
- 1
Slice onions thin. Heat oil in a large skillet over medium-high heat, add onions with a pinch of salt, and cook 8–10 minutes, stirring often, until deep golden brown and caramelized.
- 2
Add sliced mushrooms to the skillet and cook 3–4 minutes until softened and any liquid evaporates. Stir in thyme, then remove from heat and let cool 2 minutes.
- 3
Unroll thawed puff pastry on a work surface. Spread caramelized onion and mushroom mixture evenly over it, leaving a 0.5-inch border. Sprinkle shredded cheese over the filling.
- 4
Starting at one long edge, tightly roll the pastry into a log. Place seam-side down on a parchment-lined baking sheet and curl into a snail shape if desired.
- 5
Whisk egg yolk with 1 tbsp water. Brush the pastry all over with the egg wash and sprinkle caraway seeds on top if using.
- 6
Bake at 400°F for 12–15 minutes until the pastry is puffed and deep golden brown. Cool 2 minutes, slice, and serve hot.
Tools you’ll need
- large skillet (12-inch)
- wooden spoon
- cutting board
- chef's knife
- parchment paper
- baking sheet
- small bowl (for egg wash)
- pastry brush
- oven
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