Cook the ground beef in a skillet over medium-high heat until browned, then remove excess fat.
Boil water for the ramen noodles.
Stir in peanut butter, hoisin, sriracha, soy sauce, ginger, and garlic into the beef. Add chopped red pepper and cook until tender.
Cook noodles in boiling water for about 3 minutes, then drain, reserving some cooking water.
Add a few tablespoons of cooking water to the beef mixture, then combine with drained noodles. Season with salt and pepper, top with scallions if desired, and serve.
Notes
Feel free to add more vegetables or adjust spice levels to taste.