Prepare the Vegetables: Start by heating the olive oil in a large skillet or pot over medium heat. Add the chopped onions, diced carrots, and diced celery. Sauté for about 5-7 minutes until the vegetables are tender and the onions are translucent.
Cook the Meat: Add the ground beef and ground turkey to the skillet, breaking it apart with a spatula. Cook until the meat is browned and no longer pink, about 7-10 minutes.
Add Garlic and Spices: Stir in the minced garlic, dried oregano, dried basil, and red pepper flakes (if using). Cook for an additional minute until fragrant.
Incorporate Tomato Ingredients: Pour in the crushed tomatoes and add the tomato paste. Stir to combine everything well.
Add Broth: Pour in the vegetable or chicken broth and bring the mixture to a simmer.
Simmer: Reduce the heat to low and allow the sauce to simmer uncovered for 20-30 minutes, stirring occasionally. This will help deepen the flavors and thicken the sauce.
Season: Taste the sauce and season with salt and pepper as needed.
Serve: Spoon the Bolognese sauce over cooked spaghetti or your preferred pasta. Garnish with fresh basil leaves and a sprinkle of grated Parmesan cheese.