Put 400 g of flour in a bowl and make a depression in the middle. Crumble the yeast, dissolve with 1 teaspoon sugar in 200 ml lukewarm water. Pour into the hollow and mix with some flour from the edge to the pre-dough.
Cover and leave to rise in a warm place for about 15 minutes. Add 1 tsp salt and 2 tbsp oil to the pre-dough. Knead everything to a smooth dough (if the dough is too firm, add about 2 tablespoons of water).
Cover and leave to rise for a further 30 minutes.
Peel and finely dice the onion and garlic. Heat 1 tablespoon of oil in a small pot. Fry the onion and garlic until transparent. Add the tomatoes. Season with salt, pepper and 1 pinch of sugar. Simmer on low heat for 15-20 minutes, stirring occasionally.
Season tomato sauce with salt and pepper. Cut mozzarella into thin slices, finely grate parmesan.
Knead the dough once again on a floured work surface, cut in half and form into balls. Roll out each ball into a round shape (approx. 24 cm Ø) and place 1 pizza base on a baking tray lined with baking paper.
Spread half of the tomato sauce on each, sprinkle with thyme and cheese or cover with cheese. Bake the pizzas one after the other in a preheated oven (electric cooker: 250 °C/circulating air: 225 °C/gas: see manufacturer) for 13-15 minutes.
Wash dandelion and flowers, dab dry. Cut leaves roughly, pluck petals. Take out finished pizzas and cover with half ham and half dandelion, sprinkle with petals.