In the meantime, in a large frying pan over low heat, heat the oil. Sauté the onions until they are soft but not brown, about 20 minutes. Add the Schinkenspeck, remove from heat and set aside to cool (it will cook in the oven later).
In a bowl, whisk together the sour cream, eggs, caraway seeds and salt. Sprinkle the flour over the onion mixture, add the egg mixture and stir it all together with a wooden spoon.
Preheat the oven to 350°F and grease a pan or line it with parchment. Ideally, use a 15-inch deep-dish pizza pan. Transfer the dough to a lightly floured surface and roll it out to fit the shape of your pan, with an additional 2 inches of dough on all edges. Lay it out on the pan, creating a 2-inch-high “curb” around the edges to contain the filling.
Using a spatula, spread the filling over the dough. Bake until the crust is crispy and golden brown, about 45 minutes. Cool and cut into wedges. Prost!