Wash and dry the peppers, place them on a baking sheet and bake them whole at 200°C for about 20 minutes, turning them halfway through cooking. When the skin appears well colored, remove them from the oven and transfer them to a bowl, then cover them with a plate or foil and let them cool completely.
Meanwhile, toast the almonds in a nonstick pan for a few minutes, without adding oil. Stir them over high heat, letting them color, but not burn. Then remove them from the heat and transfer them to a bowl to cool.
Remove the skin, core, and seeds from the now-cold peppers, collect the pulp in a long, narrow mug, and blend it with an immersion blender along with grana padano cheese, a drizzle of oil, salt, and some fresh basil leaves.
In a skillet, sauté the garlic with a drizzle of oil, then add the passata, season with salt, and let it come to a boil. Cook for about 10 minutes. Then turn off, remove from the heat and add the bell pepper puree, then mix completely and keep aside.
Cook the tortellini in boiling salted water, drain and transfer to a large plate, then season with a tablespoon of oil and stir.
Spread the roasted bell pepper sauce in 2 bowls, arrange the tortellini on each plate, and top with some more sauce, a few basil leaves, and almonds coarsely chopped with a knife.
Serve immediately.