Pumpkin Lobster Mac and Cheese

INGREDIENTS

• 1 (12 ounce) package uncooked shell pasta
• 2 tablespoons margarine
• 1 tablespoon minced shallot
• 1 tablespoon all-purpose flour
• 1 (12 fluid ounce) can evaporated milk
• 1 (8 ounce) package shredded Cheddar cheese
• 1 (8 ounce) container mascarpone cheese
• 1 cup canned pumpkin puree
• 1 teaspoon lemon zest
• salt and ground black pepper to taste
• 1 pinch garlic powder, or to taste
• 1 pinch paprika, or to taste
• 1 pinch ground nutmeg, or to taste
• 2 dashes hot sauce, or to taste
• 1 pound cooked lobster tails, peeled and chopped
• 1 (12 ounce) package green peas, thawed if frozen
• 1/2 cup panko bread crumbs
• 1/3 cup grated Parmesan cheese
• 2 tablespoons margarine, melted