Add the oil, salt, flour, yeast, warm water, and sugar to a large mixing bowl.
Mix with an electric mixer fitted with a dough hook until a shaggy dough forms.
Grease a baking dish with olive oil, then place the dough inside. Press it down so it reaches the corners of the dish.
Cover with plastic wrap and let it rise for 1 hour.
Once the dough has risen, preheat the oven to 375°F.
Grease your fingers and dimple the dough all over.
Arrange the rosemary sprigs into the shape of a Christmas tree, then add cherry tomatoes as ornaments.
Peel and slice the onion, scattering the pieces across the dough. Arrange some slices into a star at the top of the tree.
Place a slice of tomato at the base of the rosemary tree.
Sprinkle with a little more salt if you want, and bake for 25 minutes until golden. Enjoy!