In a large bowl, mix flour, yeast, sugar, and salt. Add the oil/butter, first egg and warm water. Mix until dough starts to form a moist ball.

Remove dough from bowl and knead for a few minutes on a floured surface. When it's smooth and soft, return to bowl, cover with plastic wrap and let rest in a warm place for 30 minutes.

Meanwhile, cube the bacon and slice onions into thin rings. Heat some oil in a large frying pan and add onions and bacon. Briefly saute on medium-high then turn to low heat and let cook for 15 minutes, until very soft.

In a small bowl, beat another egg and mix with the sour cream, caraway seeds, a pinch of salt and pepper, and paprika if using. Set aside.

Preheat oven to 200°C/400°F (For convection oven 180°C/350°F). Grease a large baking pan (or pizza pan, or 2 pie dishes). Role out dough to the size of the pan.

Place on pan and form edges around outside.

Spread the cooked onions and bacon evenly over the dough. Pour over the sour cream sauce and sprinkle with a bit of salt & pepper.

Bake Zwiebelkuchen on middle rack for 30-40 minutes or until golden brown (though keep an eye on it after 20-25 minutes. Depending on your oven, it could be done sooner!).

You can make a round one too, like pizza!