In a small bowl mix all the spices (salt, pepper, smoked paprika and oregano).
Cut the onion in half and slice lengthwise. Take the garlic and chop it into mid-size pieces. Put everything in a bowl.
Cut chicken breast pieces in half and beat a little bit. Then sprinkle each side with spices, transfer chicken to a bowl with onions and garlic and add mayonnaise. Gently mix so all chicken pieces are covered in mayonnaise. Leave to marinate for an 10-60min or even overnight.
Preheat the oven to 180C (grill function).
Preheat the pan to a bit more than medium heat and pour about 2 tbsp. of sunflower oil. Pour breadcrumbs into the plate and dip each chicken side so that all the chicken is covered in a thin layer of breadcrumbs (you don’t need to use onion and garlic, they were used only for marinating). Cook in the pan till each side becomes golden brown.
Add more oil and lower the heat if the chicken starts burning.
Place chicken on a paper towel to drain extra oil. Then put it on the baking tray. Put 1 tsp of mayonnaise on the chicken and spread it. Then add cheese and place in the oven for 7-10min (cheese must melt and get a little bit brown).
Serve with mashed potatoes, rice and/or salad.