Step 1: Prepare the Flaky Gluten-Free Crust

Chill the Butter: Cube the salted butter into 1-inch pieces and place them in the freezer for at least 10–15 minutes. Cold butter is key to creating flaky layers in gluten-free dough.

Mix the Liquid Ingredients: In a small bowl, whisk together the ice water, sour cream, and apple cider vinegar until smooth. Set aside.

Form the Dough: In a stand mixer fitted with the paddle attachment, combine the gluten-free flour and salt. Add the chilled butter and mix on medium-low until the mixture resembles coarse, sandy crumbs—some small butter pieces are okay.

Add Liquid: Add the liquid mixture 1 tablespoon at a time, mixing on low speed. Add just enough until the dough starts to come together and pulls away from the sides. Avoid overmixing.

Roll the Dough: Turn out the dough onto a floured surface or between sheets of parchment/plastic wrap. Shape into a disk and roll to about ¼" to ½" thickness.

Transfer to Pie Pan: Carefully flip the dough into your pie plate. Press it gently into the bottom and up the sides. Trim excess dough, then crimp or flute the edges with your fingers. You could also use a tart tin pan.

Chill and Par-Bake: Chill the crust in the fridge for 15 minutes. Meanwhile, preheat the oven to 375°F. Then bake the crust for 25 minutes for a fully baked crust, or 12 minutes for a par-baked crust.

Step 2: Prepare the Filling

Cook the Aromatics: In a skillet over medium heat, cook chopped bacon and red onion until the bacon is crispy and onions are tender (about 7–9 minutes). Stir in chopped spinach and cook until just wilted. Remove from heat and let cool slightly.

Make the Custard: In a large bowl, whisk together eggs until smooth. Add sour cream, half and half, mozzarella, Swiss, salt, and pepper. Stir until well combined.

Combine: Fold in the cooled bacon-spinach mixture into the egg mixture.

Step 3: Assemble & Bake

Reduce oven temperature to 325°F.

Pour the creamy Filling into the par-baked crust and smooth the top.

Bake for 45–50 minutes or until the center is set and a knife inserted comes out clean. If the crust starts to brown too much, tent the edges with foil.

Rest & Serve: Let the whole quiche rest for at least 10 minutes before slicing. This helps the custard finish setting up and makes for cleaner slices.