In a large bowl, sift in 1 1/2 cup all-purpose flour, and use a tablespoon to scoop out 2 tbsp flour to save for later. With a fork, mix in 4 tbsp water, 1 tbsp shortening, and 1/4 tsp baking powder. Knead until the dough is smooth, then cover with a towel and allow to rest for 10 minutes.
Chop 10 oz peeled shrimp into cubes. Preheat the oven to 400°F.
Dust a working surface and a rolling pin with the flour you saved earlier, then roll the dough until it’s 1-2 mm thick.
Roll the flattened dough onto the rolling pin, then transfer it into a round baking dish (ours is 1.5 inches high, 9 inches in diameter).
Trim the edges, then use a fork to press down the sides as well as poke holes in the bottom, like so.
Bake in the preheated oven for 10 minutes.
Heat a non-stick skillet over medium heat. Add 1 tbsp unsalted butter, 1/2 tbsp garlic, and 2 oz onions and stir until the onion becomes translucent (about 2 minutes).
Add the chopped shrimp along with paprika, pepper, and salt (1/2 tsp each) and turn the heat on high. Stir until the shrimp turns red on the outside (about 1 minute).
Add 8 oz mushrooms and continue to stir, until the mushrooms are softened and shiny. This takes about 2-3 minutes. Transfer the filling to a bowl and let it cool, possibly in front of a fan.
Whisk in the bowl 3 medium eggs, 1/2 cup whole milk, 4 tbsp heavy cream, and 2 tbsp parsley.
Gently transfer the wet filling into the pre-baked crust. Arrange 2 oz asparagus on top, like so. Bake in the oven, on the bottom rack, for 25 minutes, at the same temperature.
Allow to cool for 5 minutes, then serve the quiche, a quarter for each serving.