Chicken paprika

This is a lovely recipe i made yesterday and the sauce was super delicious.Since i was cooking for just myself,i halved the quantities and added some chili flakes too as i like spicy food.
Chicken Paprika
ingredients
.2 tablespoon butter
.1/4 cup olive olive
.1 cup chopped onion
.3 pounds chicken thigh flattened with mallet
1 tablespoon hungarian paprika
salt and pepper to taste
1/4 cup chicken stock
.1/4 cup white wine
.1 large egg yolk
.1/2 cup sour cream
parsley to garnish
Method
.Heat butter and 2 tablespoon olive oil in a skillet over medium high till foam subsides
.Add onion and sauté stirring for 3 minutes.
.Add chicken fillets and sauté for 3 mins on each side.
.Stir in paprika ,salt,pepper and remaining 2 tablespoons of olive oil.cook stirring 2 mins
.Meanwhile bring the stock and wine to a boil in a saucepan.
.Whisk together the egg yolk and sour cream in a bowl.
.Slowly add the wine -stock mix into egg mix,whisking till the sauce is smooth.
Pour sauce over the chicken in the skillet
.Cover and simmer 8-10 mins
.Garnish with parsley and serve