Preheat oven to 400°F.
For Crust: Combine flour and brown sugar in a medium bowl. Cut in butter with pastry blender or two knives until mixture is crumbly. Press mixture into a 13 x 9-inch baking pan or dish. Bake 10 to 13 minutes until crust is very lightly browned.
For Filling: Mix brown sugar, flour, baking powder and salt in a medium bowl. Beat in eggs, corn syrup and vanilla. Stir in coconut, almonds or walnuts and chocolate chips, if desired. Spread over partially baked crust.
Reduce oven temperature to 350°F. Bake 17 to 20 minutes until set and lightly browned around edges. Cool before cutting into bars.
Variation: To make Coconut Walnut Bars, substitute 1 cup chopped walnuts for the almonds.