Boil the pierogies according to package directions. Drain. Meanwhile, in a 12-inch skillet over medium-high heat, melt the butter; cook the eggs until just scrambled, stirring constantly. Remove to a bowl.
In the same skillet, heat the peanut oil; over medium heat, cook the garlic until lightly browned. With a slotted spoon, remove the garlic to a bowl with the eggs.
In the same skillet set over medium-high heat, cook the chicken in the pan drippings until well browned and cooked through, stirring constantly. Add the salt and crushed red pepper.
Stir in the egg mixture, peanut sauce, bean sprouts, and cooked pierogies. Toss to mix well. Garnish with the chopped peanuts and scallions.