1. Crust: Mix the flour, cheese and butter tog. Chill for 1 hr. Roll into 12 balls, each for 1 crust.
2. Filling: Saute the onions in the oil. Cool.
3. Add the sour cream, egg, swiss cheese, salt and pepper.
4. Shape little crust in 12 mini-cupcake tins.
5. Add filling.
6. Bake 350 degrees for 25 to 30 minutes.