Add the flour to a large bowl. Dissolve the honey in the water and crush the fresh yeast in. Stir to dissolve and pour into the flour bowl. Stir the mixture with a spatula, and when the dough starts coming together add the salt. Knead the dough on a floured surface, optionally adding 2 tbsp of olive oil. Roll the dough into a ball, put it back in the bowl, cover it with cling film and let it rise for a couple of hours (or preferably overnight) in a warm place.
Clean the leeks, remove root end and part of the darker leaves. Cut in half lengthways, rinse under cold water to remove dirt. Pat the leeks dry and place on a cutting board with the cut facing down. Slice leeks into 1-cm bits. Melt the butter in a pan on medium heat, then add leeks and sauté for a couple of minutes. Add salt and white pepper and keep sweating the leeks on medium heat until soft, about 4-5 minutes. Remove from heat when soft.
When the dough is ready, divide it into two balls and stretch them out to form two round shapes. Place sliced mozzarella onto the dough, add sautéed leeks and pipe mascarpone here and there. Top with a thin circle of olive oil over the ingredients.
Bake in the preheated oven at 250°C (480°F) for about 10 minutes, until the cheese has melted and the crust has lightly browned.
Notes
Depending on oven types, baking time may vary. Baking the pizza on a preheated stone in a fan-forced oven like I did, it may take as little as 8 minutes for the pizza to be ready.