Bring 500 ml of water to the boil in a saucepan and simmer the lentils for 5 - 7 minutes.
In the meantime, clean the bell pepper and shallot and cut into pieces. The clove of garlic is finely chopped. Wash the tomatoes and puree with a hand blender.
Heat the oil in a pan and lightly fry the shallots. Then add the peppers and fry for about 4 minutes. Add the cooked lentils to the pan.
Strain the tomatoes in a fine sieve and add to the pan. Now heat and add the finely chopped garlic. Simmer on low to medium level for 4 - 5 minutes. Take the pan off the heat and puree everything with a hand blender. Add the chopped basil.