Soak peas with a spoon of baking soda for 12 hours.
Boil the peas, and in the meantime cut the mushrooms finely and fry them on high heat in a little olive oil.
Select mushrooms from frying pan to the side.
Grate carrots on a grater, cut onion. Bell peppers cut into strips and send to fry in the oil in which the mushrooms were fried.
Cut the olives into slices.
Cut the potatoes into cubes.
At the end of cooking peas, add a teaspoon of soda. When the peas are ready, drain the water in which it is cooked and add boiling water, potatoes, mushrooms, onions and carrots, pepper, bay leaf and black pepper.
Cook all together until the potatoes are ready and add herbs, olives and juice of half a lemon. Salt. The soup is ready.