Heat bacon in a large skillet to medium-high. Cook until barely crisp, about 6-8 minutes. Remove bacon with a slotted spoon and transfer to a paper towel lined plate to drain. Reserve bacon fat.

Reduce heat to medium and add onions. Cook just until the onions soften, about 4-5 minutes. If you feel like you need a bit more fat in the pan while the onions cook, add a bit of the reserved bacon grease back in. Once cooked, remove onions from heat and let cool to room temperature.

Mix fromage blanc, creme fraiche and nutmeg together in a bowl. Season with salt and pepper.

Heat your oven to broil and make sure oven rack is as close to the bottom of the oven as it will go.

Dust a work surface with flour. Roll one ball of pizza dough into a 5" round, or a bit thinner if you can without tearing the dough. Transfer the dough to a cold cast-iron skillet. Turn on heat to medium-high and cook for 5-7 minutes, until the crust begins to brown on the bottom. Dock the dough with a fork through the cooking process to remove any large air bubbles. Transfer dough to a baking sheet and repeat with the remaining ball of dough.

Spread cheese mixture over both tart rounds, dividing evenly amongst the two. Top with onions and bacon. Broil for 5-6 minutes or until the tarts are browned and golden. Remove from heat and serve immediately.