Ingredients:
Puff Pastry
- 300g/10½oz plain flour
- pinch salt
- 50g/1¾oz butter, chilled and cut into cubes
- 120g/4½oz butter, frozen
- water
Filling:
- 4 tablespoons salted butter, divided
- 5-6 ounces crimini or button mushrooms, sliced paper thin
- 2 medium yellow onions, thinly sliced
- 1/4 teaspoon dried thyme
- 1 1/2 tablespoon balsamic vinegar
- 1/4 teaspoon garlic powder
- salt and pepper, to taste
- ½ cup of shredded Parmesan
- 1 egg
Step 1: mix flour and butter to a crumbly texture
- Mix the dry ingredients ( 300g flour and a pinch of salt) then run 50g of cubed, chilled butter into the flour. It will feel a bit like breadcrumbs.
- Add water a tablespoon at a time until a nice stretchy dough forms
Step 2: “envelope” folds
- roll the dough out into a large rectangle (it will take some "elbow grease"). Then shred ¼ of the 120g of butter (basically a frozen stick of butter) on the bottom third of the rectangle.
- Fold the top of the dough toward you ⅔ of the way and then fold the bottom third up on top of it.
- Turn it 90 degrees, and I usually flip it so the butter side is on the bottom. Continue to follow this pattern until you are out of butter.
- Wrap it flat and put it the fridge- you will want to bake it cold.
- Preheat the oven to 400ºF
Step 3: make the filling
- Throw in a pat of butter (part of 4 tbsp), add ¼ tsp garlic and ¼ tsp thyme let that stew a bit. The thyme will pop like rice crispies so beware that it is both fun and dangerous.
- Add onions to begin caramelizing. Be sure to keep some movement in the pan so that nothing burns. About halfway through cooking, I like to add water to the pan and close the lid. It will keep the onions hydrated while caramelizing and helps speed up the process.
- Add more butter and mushrooms to caramelize those as well with some salt to bring out the flavors.
- Finally, add 1 ½ tbsp (or if you are like me a splash lol) of balsamic vinegar to deglaze the pan and add a bit more zing to the flavor palette.
- Set this mixture aside.
