Preheat the oven to 400°. Line a standard 12-cup muffin pan with foil liners. In a medium saucepan of salted water, bring the potatoes to a boil. Cook until tender, about 15 minutes; drain.
Meanwhile, in a large skillet, cook the sausage over medium-high heat, breaking up the meat, until barely pink, 3 to 4 minutes. Using a slotted spoon, transfer to a large bowl. Discard any excess grease and return to medium heat. Add the onion and bell pepper and cook, stirring, until softened, about 4 minutes. Add to the sausage and let stand for 5 minutes.
Using an electric mixer, beat the potatoes, cream, butter and 1/2 teaspoon salt until smooth.
Using your hands, combine the breadcrumbs and sausage mixture, breaking up any large pieces. Mix in the eggs; season with 1/2 teaspoon salt.
Fill each prepared muffin cup with 1/3 cup sausage mixture. Bake until browned, about 30 minutes. Let cool for 10 minutes; transfer to a platter.
Fill a pastry bag fitted with a star tip (or a resealable plastic bag with a corner cut off) with the mashed potatoes and pipe onto each cupcake.