Preheat oven to 375 degrees F. Begin by washing your chopped leeks well, draining and drying. In a medium bowl, combine the leeks, cooked sausage, eggs, oat milk, thyme, salt, and pepper, whisking till well combined.
Meanwhile form the pie dough and roll it out with a rolling pin to about 1/8-1/4" thickness. Use a 3 inch glass or cookie cutter to cut circles in the dough and put into a greased or non-stick muffin tin. You will probably have to do this in two steps, rolling out the remaining pie dough again to use the rest. Press along the sides of a greased muffin tin so the dough is thin (it does not need to reach the top). You should have enough for all 12 tins.
Pour the egg filling into the quiche dough, evenly dispersing among the cups, and bake for 25-30 minutes until cooked through and set on top. Allow to cool in the muffin tin for 5 minutes and then slide a knife around the edges, carefully lifting the quiche out the pan. Serve warm and enjoy!
Notes
I recommend using a dark nonstick muffin tin. If you don't, it may require longer cooking time or pre-baking the crust.
Other milks you can use - Hemp milk, rice milk, nut milks (if tolerated) or cow's milk. I don't recommend coconut as the flavor may be too strong.
To make gluten free, use a gluten free crust like Wholly Wholesome.
Sausage - I like to use my sausage recipe (pg53 of my Dizzy Cook cookbook) or pre-made fresh sweet Italian chicken sausage. These would be the kind that are uncooked with fresh ground meat, usually sold behind the meat counter.
To make vegetarian, leave out the sausage. You can add 3/4 cup of other mixed vegetables like broccoli or peppers. I'd also add a few spices for flavor, like garlic powder or paprika.