Into a bowl, start by adding the warm water, the sugar and the dry yeast powder, mix well.
Add the olive oil or oil and the egg, mix well again. Add the wheat flour and the salt, mix again until a dough is formed.
When you can no longer mix it with the spoon, use your hands and knead for about 8 minutes. If dough is sticking to your hands, add some more wheat flour.
Place the dough in the bowl and cover with plastic wrap, let it rest for about 10 minutes.
After the indicated time, transfer the dough to a table and sprinkle some flour on it, so it doesn't stick.
Stretch the dough into a rectangular shape with a rolling pin, make sure it’s not too thick nor too thin.
Leave a 2-finger space around the dough edges and stuff it with the grated ham, add oregano to taste, add the grated mozzarella, the tomato chopped into round slices and sliced olives to taste.
Hold one of the ends of this dough and roll it into a log shape.
Fold down the dough ends.
Transfer bread to a baking tin lined with parchment paper, cover with a cloth and let it rest for about 30 minutes.
After that, brush a beaten egg yolk over the bread, add some oregano to taste.
Bake in a preheated oven at 180°C (356°F) for 35 minutes. Baking time may vary depending on the power of your oven.
Serve.