Place the bacon slices in a cold medium-sized skillet.
Place the skillet over medium-high heat and cook until they become crunchy.
Transfer the cooked bacon to a plate lined with a kitchen towel to absorb excess oil.
Add the onions to the same skillet (and bacon oil), then season with salt and paprika.
Cook until the onions are soft, then remove the pan from the heat.
By this time, flammkuchen dough should be ready.
Preheat your oven to 215°C (425°F).
Deflate flammkuchen dough, transfer it to a countertop, and divide it into three portions.
Start to work on one portion by rolling it into an oval or rectangular shape and as thin as possible --- you need a rolling pin to get this done.
Spread a third of the creme fraiche evenly, keeping about half an inch of space from the edge of your German pizza.
Sprinkle with the mix of ground cumin, coriander, and black pepper.
Add the cooked onions on top --- try to arrange them evenly.
Place your German pizza in the oven for 15 to 18 minutes or until it turns golden and crunchy.
Remove from the oven carefully, and add the crispy bacon.
Your homemade flammkuchen is now ready for serving and slicing!