This is an authentic Mexican vegan soup made with only a few ingredients: tomatoes, tortillas, onion, garlic and guajillo chilli in a vegetable stock base. Serve with baked tortilla strips and avocado.
Cut 2 tortillas in half and then into 2cm strips. Place in a bowl and toss with avocado oil. Arrange strips in a single layer on a baking tray.
Bake in the preheated oven until the strips are crisp and light brown, about 15 minutes. Remove from oven and set aside for garnishing.
Place guajillo chilli in a saucepan with water to cover; bring to the boil. Remove from heat and let chilli soak in the hot water until soft, at least 10 minutes. Drain.
Heat olive oil in a pan over medium heat. Add onion and garlic; saute until softened, about 3 minutes. Tear remaining tortilla into pieces and add to the pan. Cook until soft, about 3 minutes. Add tomatoes; cook and stir until tender, about 5 minutes. Remove from heat and let cool, about 5 minutes.
Place tomato-tortilla mixture into a blender. Add the soaked guajillo chilli and vegetable stock. Blend until smooth. Pour into a saucepan and season with salt. If you prefer a very fine soup, you can pass it through a sieve back into the saucepan. Bring to the boil and let simmer until flavours blend, about 5 minutes. Garnish with baked tortilla strips and avocado slices.