To prepare the dough:
- Combine the flour and salt in a large bowl and use a pastry cutter or the backs of two forks to cut the Kerrygold unsalted butter into the dry ingredients until pea-sized clumps exist throughout.
- Add the ice water and gently fluff together until the mixture can come together into a dough that isn’t too wet but packs. You may need an additional couple teaspoons of water.
- Form the dough into a disk, wrap in plastic wrap, and refrigerate until chilled, at least an hour.
To prepare the filling:
- Heat one teaspoon oil in a large skillet over medium heat. Brown and break up the sausage until cooked through and browned.
- Remove from skillet, leaving any grease that may exist in the bottom of the pan.
- Add an additional teaspoon of oil and then cook the onions over medium heat until they are translucent.
- Add the kale, red pepper flakes, and 1/4 teaspoon of salt to the pan and cook until the kale is wilted and no longer producing moisture, about 3-4 minutes.
- Remove from the pan.
To prepare the quiche:
- Preheat the oven to 375 and roll out the chilled pie dough on a lightly floured surface until the dough is approximately 1-1/2 inches larger than your tart pan with a removable bottom on all sides.
- Roll the dough back onto the floured rolling pin and unroll the dough into the pan. Leave a 1” border on all sides and trim off any excess.
- Fold the sides under and pinch together, leaving 1/4” of dough extending over the sides of the pan.
- Place a crumpled piece of parchment paper into the bottom of the pan on top of the pie dough and fill the pan with pie weights, dried rice or beans.
- Par-bake in the oven for 10 minutes, then remove the weights and parchment and bake for an additional 10-15 minutes or until the bottom no longer looks wet. In the meantime, whisk together the milk, 4 of the eggs, remaining 3/4 teaspoon of salt, and pepper in a large bowl.
- Once the pie crust is baked, crack the egg into a small bowl without breaking the yolk and use a pastry brush to brush the entire insides of the pie with egg white.
- Sprinkle 1 cup of Kerrygold swiss cheese into the bottom of the baked crust and top with the browned sausage crumbles and the kale and onion mixture. Sprinkle the remaining 1/4 cup of Kerrygold swiss cheese and then carefully pour the egg mixture on top. Whisk together the egg you brushed on the pie crust and brush the entire rim of the pie crust with a thin layer.
- Bake in the preheated oven for about 35 minutes or until the top is golden and the insides are no longer jiggly. Cool slightly and enjoy!
The egg wash is entirely optional. The brushed egg white serves as an extra layer of protection for the crust and the whisked whole egg helps with browning. Neither are necessary so feel free to skip this step if needed.