Preheat your oven to 400°F.
Peel and dice the sweet potato into chunks. Boil in lightly salted water until tender, about 15-20 minutes.
Meanwhile, dice the carrot, onion, and mince the garlic.
Heat olive oil in a skillet over medium heat. Add the diced onion and carrot, sautéing until softened, about 4-5 minutes.
Add minced garlic and cook for an additional minute.
Stir in the lean ground beef, breaking it apart, and cook until browned. Drain excess fat if necessary.
Mix in tomato paste and low-sodium beef broth, allowing the mixture to simmer for 3-4 minutes.
Gently fold in the green peas. Season with salt and pepper.
Drain the sweet potato and mash it with nonfat Greek yogurt until smooth. Season lightly with salt and pepper as desired.
Spread the beef and vegetable mixture evenly in an ovenproof dish. Top with the creamy sweet potato mash, spreading it out to cover the filling completely.
Bake in the preheated oven for 10-12 minutes until everything is heated through and the topping is slightly golden.
Remove from oven, let cool briefly, and serve warm.