For the crust:
2 cups unbleached all-purpose flour
1 tsp salt
1/4 tsp sugar
6 ounces chilled butter
4 Tbsp chilled vegetable shortening
a scant half cup ice water, or more as needed
For the filling:
2 medium-sized onions, sliced thin in half circles
1 Tbsp olive oil
1 Tbsp butter
Salt and pepper
1 1/2 cups whipping cream
2.5-3 oz feta cheese
1/8 tsp fresh black pepper
1 Tbsp butter (optional)
To make the dough: in a food processor fitted with a blade, add all crust ingredients except for water. Pulse a few times to mix. Begin adding water just until a ball of dough begins to form. Do not over-pulse.
Remove dough and work on a lightly floured surface until you can shape the dough into one flat disk for one large quiche, or two flat discs if making a smaller quiche in tart pan . You can also place in muffin tins to make individual quiches.
Wrap in plastic and place in fridge for 1-2 hours or overnight.
To make the caramelized onions, heat olive oil and butter in a large sautÚ pan over medium low heat. Add onions and sautÚ for 10-15 minutes, until golden and completely soft. Set aside. (This step can be done the day before if desired).
If making your own crust, preheat oven to 400 ║.
Roll out crust(s) on a lightly floured surface until 1/4 inch thick. Carefully roll the crust onto your rolling pin and lay on top of spring form pan or tart pan. Gently push the crust into the pan using tips of fingers and thumbs.
Prick the bottom of the crust with a fork all over. You can get fancy with the edges of the crust, or just leave for a rustic look. Bake for 7-9 minutes. Remove from oven and let cool slightly.
Reduce oven temperature to 375 degrees. Spread onions evenly on top of quiche crust.
Whisk together eggs, cream and pepper. Crumble feta into small pieces into mixture and fold gently. Pour on top of onions into prepared quiche crust, taking care to try and evenly distribute the cheese. If desired, cut one additional Tbsp of butter into small pieces and dot on top of quiche before baking. (This step is optional).
Bake for 25-30 minutes. Serve warm or room temperature.