Sofrito Bolognese

Name: Sofrito Bolognese
Ingredients: 1 large yellow onion, roughly chopped; 1 large green bell pepper, roughly chopped; 6 large garlic cloves; 2 Tbsp. extra-virgin olive oil; 1 lb. ground beef (or you can use half pork and half beef); 1 Tbsp. dried oregano; ½ tsp. crushed red pepper flakes (optional); 2 tsp. kosher salt, plus more; Freshly cracked black pepper; 1 4.5-oz. tube tomato paste (about ½ cup); 1½ cups dry white wine; 2 cups unsalted beef, chicken, or vegetable stock; 1½ tsp. sazón with achiote; 1 lb. spaghetti (or another pasta of choice); 1 Tbsp. unsalted butter; Grated Parmesan (for serving); ¼ cup (packed) finely chopped cilantro leaves