Preheat your oven to 250°C (480°F) or as high as your oven safely allows. If using a pizza stone, place it in the oven to heat. In a large mixing bowl, combine flour, water, olive oil, and salt to form the dough. Knead it for 5-7 minutes until smooth and elastic. Cover the dough with a clean cloth and let it rest for 15 minutes.

While the dough rests, prepare the topping base by mixing crème fraîche, sour cream, and nutmeg in a small bowl. Stir until smooth and creamy. Taste and adjust with a pinch of salt if needed, keeping the flavours balanced and subtle.

Prepare the onions and bacon. Thinly slice the onion into rings for even cooking. For bacon, use smoked lardons or strips, ensuring they are bite sized. If the bacon is particularly fatty, briefly render it in a skillet over medium heat to remove excess fat, but do not fully cook.

Divide the dough into two equal portions for easier handling. Roll out each portion on a floured surface into a very thin oval or rectangle, approximately 2-3mm thick. Thinness is key to achieving the traditional crisp texture of Flammkuchen.

Carefully transfer the rolled out dough onto parchment paper or a pizza peel for easy handling. Spread a thin, even layer of the crème fraîche mixture over the surface of each dough base, leaving a small border around the edges.

Top the Flammkuchen with sliced onions and bacon. Distribute them evenly to ensure each bite offers a harmonious blend of flavours. Sprinkle freshly ground black pepper over the toppings for an added layer of aroma.

Transfer the prepared Flammkuchen to the hot oven. Bake directly on the pizza stone or baking sheet for 8-10 minutes, or until the edges are golden and crispy, and the bacon is fully cooked. Rotate the baking sheet halfway through for even cooking if necessary.

Remove the Flammkuchen from the oven and let it cool for a minute before slicing. Serve immediately on a wooden board or platter. For an authentic touch, pair with a crisp white wine or a light German lager. Garnish with a sprinkle of fresh chives or parsley for added colour and freshness, if desired.