Melt 45g of butter in a large frying pan over medium-high heat. Add the chicken and cook until browned on both sides and no longer pink in the centre, about 10 minutes; place into a 23x33cm or similar sized baking dish and set aside.
Reduce the heat to medium and melt the remaining butter in the pan. Stir in the garlic and onions and cook for 2 minutes, stirring constantly until the onion starts to soften. Stir in the flour and continue cooking 5 minutes more. Add the vodka and bring to a simmer over medium-high heat, stirring constantly. Allow to simmer for 2 minutes, then stir in the tomato puree, chicken stock, salt, pepper, parsley, soured cream and Feta cheese. Reduce heat to medium-low and simmer 20 to 30 minutes stirring frequently.
Preheat oven to 180 C / Gas 4.
Pour the hot sauce over the chicken breasts; bake in preheated oven until the top has browned, about 20 minutes.