Bake pecans on a baking sheet at 350° for 15 minutes or until golden brown, stirring once.
Bring butter, brown sugar, and cream to a boil in a 2-qt. saucepan over medium heat, stirring often; boil, stirring often, 1 minute. Remove from heat, and whisk in powdered sugar and vanilla until smooth. Add toasted pecans; stir gently 3 minutes or until frosting begins to cool and thicken slightly.