Recipe from my grandmother! She always cooked potatoes like this for our family

Recipe from my grandmother! She always cooked potatoes like this for our family!
Ingredients:
500g potatoes
20g butter
50 ml milk
egg
Salt
150g flour
Onion
carrot
300g mushrooms
salt pepper
50g mozzarella cheese
dill
Vegetable salad:
2 cucumbers
tomato
radish
paprika