Meat Sauce

1 cup minced onion
2 cloves garlic, minced
1/2 cup minced celery
1/4 cup green pepper, chopped fine
2 tablespoons butter
1-1/2 pounds ground beef
1/2 teaspoon white sugar
1 teaspoon salt
1/2 teaspoon fresh cracked black pepper
6 ounces fresh chopped mushrooms
1 (6 ounce) can tomato paste
1 (28 ounce) can diced tomatoes
2 (10.5 ounce) cans beef broth
2 teaspoons dried basil
2 teaspoons dried oregano
1 teaspoon thyme

Brown ground beef.  Combine all ingredients in crockpot on low for 6-8 hours.  Serve over pasta.