Rosemary Spinach Mushroom Alpine Quiche

Crust:
8 Tbs. ice-cold butter, cubed into 1″ pieces
2 1/4 cups all-purpose flour

1 Tbs. fresh rosemary, finely chopped
1 large egg
1 Tbs. apple cider vinegar
3-4 Tbs. ice cold water

Filling:
3 Tbs. butter
1 small sweet onion, finely chopped
8 oz. baby bella mushrooms, sliced
1 large portabella mushroom, sliced
2 cups fresh baby spinach
1 tsp. fresh rosemary, finely chopped
4 oz. mascarpone cheese
3 large eggs
sea salt and pepper
2 cups Alpine Swiss and Gruyere cheeses, coarsely grated

Preheat oven to 400 degrees.

Combine the flour, butter, egg, rosemary, and vinegar, in a food processor. Pulse until crumbly. Drizzle in the ice water and pulse again until a bit more doughy and still slightly beady.

Transfer to parchment paper and form into a large disc.

Roll between two sheets of parchment into a 9-10″ crust.

Transfer crust to a pie plate, fluting the edges.

Melt the butter in a large skillet over medium heat.
Add the onions and sauté until soft.
Add the slices baby bella mushrooms and season well with salt and pepper. Cover, stirring every so often, until soft and juicy.
Stir in the spinach and cook until wilted. Add at least 1 tsp. fresh rosemary to season the veggies.
Remove from heat.

Melt another touch of butter and sauté the sliced portabellas until soft.

In a separate bowl, whisk together the eggs and cheeses.
Add the sauteed veggies and stir well.

Fill the prepared pie crust with the veggie- egg mixture.

Decoratively top with the cooked slices of portabella.

Bake for 35-40 minutes, until the outer crust browns and the filling is just about set.

Remove from oven and cool for several hours. 

Chill overnight for a few more hours to fully set.