The perfect onion rings

Ingredients
For the porridge:
3 tablespoons flour
1 egg
3 tablespoons olive oil
Salt
Pepper
2 large onions cut into thick rings
Sunflower oil for frying
Salt
Pepper

Implementation
To make the porridge, sift the flour and put it in a bowl with a little salt. Make a hole in the middle and add the egg, olive oil and pepper. Mix the mixture well until it is homogeneous and velvety. Let it rest for 1 hour. Cut the onions into rings, put them in ice water and leave for 30 minutes. Strain and dry well with kitchen paper. Then pour the sunflower oil in a deep pan and let it heat well. Take the onions a little at a time, dip them in the porridge and then in the hot oil until they get a nice golden color (to fry them perfectly and keep the outside crisp, do not squeeze them into the pan). When they are ready, take them out and leave them for a while on kitchen paper - they are served hot.