Cream Cheese Pastry: Beat butter and cream cheese on high until light and fluffy. Add flour, beating just until combined. Shape Cream Cheese Pastry dough into 24 balls. Place in non-stick, ungreased mini-muffin pan, shaping each into a shell. Chill 30 minutes. Prick each shell, and bake at 400° F for 10 to 12 minutes or until golden brown. Loosen edges of tart shells from pans, using a sharp knife; cool in pan for 10 minutes. Remove from pan and cool completely on wire rack. May be prepared in advance and stored in a ziploc bag.

Key Lime Mixture: Beat egg yolks at medium speed of an electric mixer until thick and lemon colored, about 4 minutes. Heat Key lime juice over medium heat until hot. Gradually stir about one-fourth of hot lime juice into egg yolks, and add to remaining hot lime juice, stirring constantly. Cook, stirring constantly over medium heat for 2 minutes, or until mixture is thickened. Remove from heat and cool 10 minutes. Add sweetened condensed milk and lime zest, stirring well. Transfer to small bowl; cover with plastic wrap, pressing plastic wrap to top of mixture. Refrigerate.

Prepare whipped cream by beating cream on high until thickened. Add confectioners' sugar; continue beating until desired consistency. Transfer to piping bag fitted with #21 star tip.

Spoon filing evenly into baked pastry shells. Pipe whipped cream on top. Garnish with lime slice.

Yield: 24 Mexican Key Lime Tartlets