In a wok or saute pan over low heat, combine oil and curry paste. Cook for 1 minute, stirring well. Increase heat to medium-high and add chicken, sugar, soy sauce, salt and garlic. Stir-fry until chicken is done.
In a medium saucepan over low heat, melt butter. Blend in flour, salt and pepper, then add milk in a steady stream. Cook and stir over medium-high heat until thick and bubbly, about 5 minutes.
Add chicken, broccoli and peanuts to sauce and cook until heated through. Serve on a bed of steamed rice.