Best Homemade Meat Sauce

Ingredients

• 2 tablespoons olive oil
• 1 large white onion, finely diced
• 5 cloves garlic, finely minced
• 1 pound Italian sausage, removed from their casings
• 1 1/2 pounds lean ground beef
• 3 cups crushed tomatoes
• 2 cups tomato sauce
• 1 (6-ounce) can tomato paste
• 2 tablespoons brown sugar
• 1 teaspoon salt, plus more to taste
• 1/2 teaspoon ground black pepper, plus more to taste
• 2 teaspoons dried basil
• 2 teaspoons Italian seasoning
• 1/2 teaspoon fennel seeds, optional
• crushed red peppers flakes, optional, to taste
• pasta, optional, cooked, for serving
• crusty bread, optional, for serving
• butter, optional, for serving