Combine flour, ground oats, sugar, and salt in a food processor. Add cubed butter and olive oil. Pulse until mixture is a sand consistency. Add 4 tbsp of water and process to form a dough. If the mixture is too crumbly, add more water (a tablespoon at a time) until a dough forms. Press the mixture into a tart shell or pie pan. Set aside.
Preheat oven to 350°F.
Bake quiche crust 10 minutes, remove from oven and let cool slightly while you prepare the filling.
Heat oil in a deep skillet over medium heat. Add shallots and bacon. Cook until shallots become translucent, about 3-5 minutes. Add spinach, tossing until it begins to wilt. Lightly season with salt and pepper. Remove from heat.
In a large bowl, combine eggs, egg whites, milk, and cream. Whisk until smooth. Mix in grated cheese, thyme, salt, and pepper. Gently fold in cooled spinach mixture.
Pour filling into prepared crust and bake for 40-50 minutes, or until a knife inserted into the center comes out clean. Remove from oven and let cool 10 minutes before cutting.