1Preheat the oven at 230C.
2Mix the dry yeast, sugar, water, and salt to a medium bowl.
3Cover the dough with plastic film and let it sit for 10 minutes in a warm place.
4Mix the whole wheat flour, white flour, and salt in a different bowl.
5Mix together the yeast and the flour, and knead for 5 minutes to make a dough.
6Add the olive oil to the dough and knead for 5 more minutes.
7Grease another bowl with cooking spray and place the dough on it. Let it sit in a warm place for 30 to 60 minutes. It should double its size.
8Place the dough on the counter and separate it in 2 pieces.
9Press them against the counter using your hands until you form a 20 centimeter disc with each dough piece.
10Place the dough discs on a cooking tray and bake for 5 minutes.
11Save them in the refrigerator. You can also store the discs in a sealed container for up to 1 month in the freezer.
12Preheat the oven at 250 C.
13Grease a skillet with cooking spray and preheat on medium-low flame.
14Add the white onion, thyme, and bay leaf to the skillet, and season with salt and pepper.
15Stir occasionally the onions for 30 minutes. They must soften and should not get brown.
16Dispose of the bay leaf, and blend the onion and thyme on a food processor until you obtain a paste. Save for later.
17Place the leek on the same skillet and cook them on medium-low for 15 minutes while stirring occasionally.
18Remove the leek from the skillet, season it with salt and pepper, and save for later.
19Cook the red and green onions for 15 minutes in the same skillet on medium-low while stirring occasionally.
20Remove the onions from the skillet and mix together with the leek.
21Add the onion paste on a pizza disc until you cover its surface.
22Place the sliced onions and leek over the paste.
23Sprinkle the mozzarella cheese over the pizza and let it cook in the oven at maximum temperature for 15 to 20 minutes. The pizza will be ready once the cheese has melted
24Turn off the oven and let the pizza cool off for a few minutes before serving.