Easy Flammkuchen - German pizza

To make the Flammkuchen base

1. Preheat the oven to 240℃/465℉/gas mark 8. Place a large baking tray on the middle shelf of the oven to heat up with the oven.
2. Add the flour and salt to the bowl of a stand mixer. If you are not using a stand mixer, add it to a large mixing bowl. Give it a quick stir.
3. Add the warm water and the olive oil to the flour and briefly combine using a spoon.
4. If you are using a stand mixer, attach the dough hook and knead the dough for 8-10 minutes. If you are doing this by hand, knead for a good 10 minutes until the dough is elastic and smooth.
5. Cut a piece of parchment paper the same size as the baking tray and place it on the work surface.
6. Place the pizza dough on the parchment paper. With a rolling pin, roll it into a thin oblong disc of 3mm - 5mm thick.

Preparing the toppings

1. Add the bacon lardons to a hot frying pan and briefly fry until they just start to brown. Don't fry them too long because they will cook further in the oven. It should only take about 2 minutes., Remove from the pan.
2. In the same pan, add a dollop of butter, or a dash of oil, along with the thinly sliced onion rings. Turn the heat to medium-low and place the lid on. Allow the onions to soften, about 3-4 minutes. Stir every minute or so to ensure they are not sticking to the pan.
3. When the onions are soft, add the teaspoon of brown sugar. Fry for a further 1-2 minutes, lid off, until the onions are a light golden brown, soft and caramelised.
4. In a small bowl, mix together the crème fraîche and sour cream. Evenly spread it across the surface of the pizza dough, leaving a gap of roughly 1cm from the edge.
5. Start by topping the pizza with the caramelised onions. Then top with the bacon lardons, spreading them out evenly. Scatter over the grated Gruyère cheese.
6. Remove the hot baking tray from the oven and slide the pizza along with the parchment paper onto the tray. Take care not to burn yourself. Bake for 15-16 minutes until the cheese is melted and the crust is a light golden brown, with a few scorched bits here and there. Important: Keep an eye on the pizza. The baking time is an approximation. All ovens are slightly different and you may get a different result with yours. Cook the pizza until it looks done, using the above visual clues.
7. Scatter some chopped chives or your favourite herbs over the top of the pizza. Cut into slices and enjoy immediately.