01 -
Preheat the oven to 375°F (190°C).
02 -
In a bowl, combine flour and salt. Cut in butter until the mixture resembles coarse crumbs. Stir in sour cream until dough forms. Wrap in plastic wrap and refrigerate for 30 minutes.
03 -
Heat olive oil in a large skillet over medium heat. Add onions and sugar, cooking until onions are caramelized, about 15 minutes. Season with salt, pepper, and thyme. Remove from heat and let cool.
04 -
Roll out the chilled dough on a floured surface to fit a 9-inch pie pan. Place the dough in the pan and trim excess.
05 -
In a separate bowl, whisk together eggs and cream. Stir in cooled onions. Pour the filling into the prepared crust.
06 -
Bake for 30-35 minutes, or until the filling is set and the top is golden. Let cool slightly before slicing.