Sweet Potato-Cauliflower Shepherd's Pie

Step 1
Preheat the oven to 400 degrees F (200 degrees C).

Step 2
Place sweet potatoes in a pot and add water to cover. Bring to a boil and cook for 15 minutes. Add cauliflower and more water if needed; cook until all vegetables are tender, about 15 minutes more. Drain. Mash sweet potatoes and cauliflower with 1/4 cup broth, butter, 1 teaspoon salt, and 1/2 teaspoon black pepper.

Step 3
Heat olive oil in a large skillet over medium-high heat. Add carrots and onion; saute until softened, about 5 minutes. Add garlic, 1 teaspoon salt, and 1/2 teaspoon black pepper; cook 5 minutes more. Add beef; cook and stir until browned and crumbly, 5 to 10 minutes.

Step 4
Sprinkle tapioca starch over the beef mixture in the skillet. Add 1 cup broth, peas, corn, and tomato paste. Bring to a boil. Reduce heat and simmer for 10 to 15 minutes. Spread beef mixture evenly in a baking dish. Top with mashed sweet potato mixture. Sprinkle Parmesan cheese on top.

Step 5
Bake in the preheated oven until slightly browned on top, about 25 minutes. Let stand 15 minutes before serving.