In a medium bowl, combine butter and cream cheese. Beat with an electric mixer on medium to high speed until combined. Add flour and macadamia nuts. Beat on low speed just until combined. Cover and chill for 30 to 60 minutes or until dough is easy to handle.

Preheat oven to 325 degrees F. Shape dough into 24 balls. Press each ball evenly into the bottoms and up the sides of 24 ungreased 1-3/4-inch muffin cups. Bake in a preheated oven for 20 to 25 minutes or until edges are golden brown. Cool slightly in pan on a wire rack.

Meanwhile, for filling, in a medium bowl, beat egg yolks with a whisk. Gradually whisk in sweetened condensed milk. Add lime peel, lime juice, and, if desired, green food coloring. Stir just until combined (mixture will thicken slightly).

Spoon about 1 tablespoon filling into each pastry cup. Bake about 10 minutes or until filling is set in center. Cool tassies in pan on a wire rack for 10 minutes. Remove tassies from the muffin cups. Transfer tassies to a wire rack; let cool. Chill for 2 to 3 hours or until completely chilled. Just before serving, top tassies with Sweetened Whipped Cream and if desired, toasted coconut. Makes 24 tassies.

In a medium bowl, combine 1/2 cup whipping cream, 1 tablespoon sugar, and 1/4 teaspoon vanilla. Beat with an electric mixer on medium speed just until soft peaks form (tips curl).

To toast coconut, spread shredded coconut in a single layer in a shallow baking pan. Bake in a 350 degree F oven for 5 to 10 minutes or until golden brown, stirring once or twice.

Place tassies in a single layer in an airtight container; cover. Store in the refrigerator for up to 2 days.

Prepare as directed through Step 1. Wrap dough in plastic wrap; freeze for up to 1 month. Thaw dough in the refrigerator for 24 hours. Continue as directed above.