Italian Sausage Bolognese Sauce

This bolognese sauce is super easy and quite delicious.  I made this the night before making the lasagna so the flavors would blend together more, plus this recipe takes about 3 hours from start to finish. 

1/4 cup extra-virgin olive oil
4 tablespoons butter
1 large yellow onion, finely chopped
2 carrots, peeled and finely chopped
5 cloves garlic, minced
1 lb hot italian sausage, ground
1 lb. sweet italian sausage, ground
1/2 cup milk
1 (28-ounce) can whole peeled tomatoes, crushed by hand, with the juices
1 cup dry red wine
2 cups beef stock (could use chicken or vegetable)
Salt and pepper

In a 6 to 8-quart, heavy-bottomed saucepan, heat olive oil and butter over medium heat. Add onion, carrot and garlic and sweat over medium heat until vegetables are translucent. Add sausage and stir into vegetables. Brown over high heat, stirring to keep meat from sticking together, about 15 to 20 minutes.

Add milk and simmer until reduced to nothing, about 10 minutes. Add tomatoes and simmer 15 minutes. Add the wine and stock, bring to a boil, lower the heat and simmer over low heat for 2 to 2 1/2 hours, stirring occasionally. Season with salt and pepper to taste and remove from heat.