Preheat oven to 350°. In a small bowl, combine flour, cashews, coconut and brown sugar. Stir in butter. Sprinkle into a greased 15x10x1-in. baking pan. Bake 20-25 minutes or until golden brown, stirring once. Cool on a wire rack., Meanwhile, in a large bowl, combine cream, milk, lime juice, zest and vanilla. Refrigerate until chilled., Fill cylinder of an ice cream maker two-thirds full; freeze according to the manufacturer’s directions., Sprinkle half of the cashew mixture into an ungreased 11x7-in. dish. Spread ice cream over top; sprinkle with remaining cashew mixture. Cover and freeze 4 hours or until firm. Garnish servings with whipped cream and lime slices if desired.