Toss Italian sausage and rice into a slow cooker for a lip-smacking comforting dish

1 tablespoon butter
5 cloves garlic, minced
1 pound Italian sausage, casings removed
2 cups Arborio or other short-grain rice
½ cup white wine
4½ cups chicken broth or stock
1 cup grated Parmesan cheese
2 tablespoons cold butter
½ teaspoon salt
¼ teaspoon pepper
1 cup half-and-half (optional)