Place potato chunks and garlic cloves in a large pot and cover with salted water; bring to a boil. Reduce heat to medium-low and simmer until tender, 10 to 15 minutes. Drain. Mash using a potato masher. Stir in Cheddar cheese, salt, and pepper until evenly mixed.
Heat oil in a large skillet over medium heat. Add onions; cook and stir until tender, about 5 minutes. Stir in vegetarian beef crumbles, mushrooms, and peas; cook until heated through, about 5 minutes. Stir in Worcestershire sauce and pepper.
Pour onion and beef crumble mixture into a deep 9-inch casserole. Spread creamed corn on top. Spread mashed potato mixture carefully over the creamed corn. Sprinkle paprika over mashed potatoes.
Bake in the preheated oven until bubbling around the sides and hot in the center, 30 to 40 minutes.