Start by combining the flour and sea salt in a large bowl. Slowly stir in the oil and water until you form a cohesive dough. If it’s too dry, add a bit more water. You want the dough to be smooth. Once you've got it, cover it with a clean cloth and let it rest for about 30 minutes. This helps in making the dough pliable for rolling later.

While the dough is resting, it's time to prepare the toppings. Start by slicing the onion thinly. The finer you slice, the more they caramelize and blend with the flammkuchen. Next, chop the smoked bacon into small pieces. This will give your dish that hearty, savory flavor. For the cheese, shredding the Gruyère helps it melt evenly.

After the resting period, it’s showtime! Dust a clean surface with flour and roll your dough into a thin, rectangular shape. Aim for about 1/8 inch thickness. The thinner, the better—trust me, you want that crispy balance with the toppings.

Now comes the fun part. Transfer the rolled-out dough onto a baking sheet. Spread the crème fraîche across the surface, leaving a small border around the edges. Sprinkle the black pepper, followed by the onions, bacon, and lastly the Gruyère cheese. Don’t forget to sprinkle a pinch of nutmeg and salt on top.

Preheat your oven to 475°F (245°C) before baking. Once hot, slide that baking sheet in. Bake for about 10-15 minutes, or until the edges are golden brown. The aroma will pull everyone into the kitchen.

Once baked, take it out of the oven and dot with small pieces of butter and thyme. Slice into squares while it's hot. Serve it immediately. The crispy edges and melty toppings will get everyone excited!