Preparation Brush cookie sheet with oil. Stir first 3 ingredients in heavy large saucepan over medium heat until sugar dissolves. Cook without stirring until mixture turns deep amber, occasionally swirling pan and brushing down sides with pastry brush dipped into water, about 15 minutes (mixture will bubble vigorously). Remove from heat. Carefully pour half of caramel into heavy small saucepan. Working quickly, place small saucepan over medium heat; add nuts and stir until coated. Pour out nut mixture onto prepared cookie sheet, spreading evenly. Set aside. Add cream and butter to remaining hot caramel mixture in large saucepan. Boil until smooth and slightly thickened, whisking often, about 5 minutes. Add orange peel. Transfer sauce to jar; cool. Cool praline completely and chop. (Praline and sauce can be made 2 weeks ahead. Cover separately chill. Bring both to room temperature before using.)
Preparation Brush cookie sheet with oil. Stir first 3 ingredients in heavy large saucepan over medium heat until sugar dissolves. Cook without stirring until mixture turns deep amber, occasionally swirling pan and brushing down sides with pastry brush dipped into water, about 15 minutes (mixture will bubble vigorously). Remove from heat. Carefully pour half of caramel into heavy small saucepan. Working quickly, place small saucepan over medium heat; add nuts and stir until coated. Pour out nut mixture onto prepared cookie sheet, spreading evenly. Set aside. Add cream and butter to remaining hot caramel mixture in large saucepan. Boil until smooth and slightly thickened, whisking often, about 5 minutes. Add orange peel. Transfer sauce to jar; cool. Cool praline completely and chop. (Praline and sauce can be made 2 weeks ahead. Cover separately chill. Bring both to room temperature before using.)