Curried Shrimp with Peanuts

Melt butter in a heavy saucepan over low heat; whisk in flour and curry powder until smooth. Cook, whisking constantly, 1 minute. Gradually whisk in milk, next 4 ingredients, and, if desired, dried crushed red pepper. Increase heat to medium, and cook, whisking constantly, 5 to 6 minutes or until mixture is thickened and bubbly. Stir in shrimp, lime juice, and salt. Reduce heat to medium-low, and cook, stirring often, 5 minutes or just until shrimp turn pink. Serve with desired toppings.