Pre-heat your oven to 425 degrees Fahrenheit, and adjust your oven rack to the lower third of the oven. Grease your muffin tin with baking spray.
Begin by making the crusts. Add 1 3/4 cups flour and 1/4 tsp salt to a large bowl and whisk together.
Add your 1/2 cup of cold lard, shortening, or butter to the flour mixture and cut in with a pastry cutter or fork.
Add the iced water 1 tablespoon at a time until you have created a shaggy dough. Expect to use 7-8 tablespoons, possibly less. Do not let the dough become sticky. Keep the bowl of ice around; you will need it again.
Fold the dough over with a spatula or your hand just until the dough is shaped into a ball at the base of the bowl. Use your spatula to cut the dough into 6 equal pie wedges, then divide each of those 6 in half. You now have 12 wedges total.
Add each of your 12 wedges to a section in your muffin tin, pointy side up.
Dip your fingers into the bowl of ice water to make sure your fingers are cold, then press the first wedge down into the muffin tin. Mold the crust so the bottom and sides are evenly covered. Whenever the crust starts feeling sticky, swish your fingers in the ice water again. Repeat for all 12 sections.
Place your crusts into the oven. Bake for 12 minutes, or until the crusts just start turning golden.
While your crusts are baking, prepare your filling. Begin heating 1 teaspoon of olive oil in a small saute pan over medium high heat.
Add your 1/2 diced onion, 1/2 teaspoon sugar, 1/4 teaspoon of ground nutmeg, and 1/4 teaspoon of garlic powder (or 1 clove minced garlic). Saute until transparent and fragrant. Reduce the heat to medium low.
Add 1 cup chopped swiss chard. Add either 1/2 teaspoon lemon juice or a splash of white wine. Continue to cook until the liquid has cooked away, then remove from the heat.
To create your egg mixture, crack 4 large eggs into a bowl, ideally one that has a pouring spout. Add 1/2 cup milk and 1/2 cup heavy cream. Whisk the mixture until homogenous.
Once your crusts have been removed, reduce the oven temperature to 350 degrees Fahrenheit. You may begin adding your filling to the crusts right away. First, add the swiss chard mixture to each of the crusts. Next, pour the egg mixture into the crusts. Finally, top the filling with the 6 ounces of mixed swiss and gruyere shredded cheeses.
Return the muffin tin to the oven and bake for 15-20 minutes, or until a wooden skewer comes out clean. Let cool for 5-10 minutes before removing the quiches from the muffin tin. Serve immediately, or cool completely before refrigerating or freezing for later.