Melt butter in a 4 litre saucepan over medium heat.
Sprinkle pork chops with salt and pepper on both sides. Place in saucepan. Stir in onion and garlic. Cook 3 minutes; turn pork chops and cook 3 more minutes. Stir in basil, tomatoes, mushrooms, milk and soup.
Reduce heat to low, cover and simmer. After 30 minutes turn chops, stir and simmer 30 minutes more.
To serve; pour sauce over chops and top with a teaspoon of sour cream on each chop.