Step 1
Stir milk and 1/2 cup plus 1 tablespoon flour together in a small saucepan. Cook stirring constantly over medium heat until thickened and bubbly about 5 minutes. Pour into a bowl; place a piece of plastic wrap directly on the surface to prevent a skin from forming. Let cool completely about 30 minutes.
Step 2
Transfer cooled milk mixture to a large bowl. Add white sugar butter shortening vanilla extract and almond extract. Beat with an electric mixer on high speed until frosting is light and creamy about 5 minutes. Divide frosting among 3 small bowls and tint by beating in enough food coloring to achieve 3 distinct shades of green. Transfer to piping bags fitted with small medium and large star tips.
Step 3
Position racks in upper and lower thirds of the oven and preheat to 375 degrees F (190 degrees C). Lightly grease 2 large baking sheets. Place 1 tablespoon sugar on a small rimmed plate.
Step 4
Beat butter shortening 1/2 cup white sugar and powdered sugar for cookies together with an electric mixer in a large bowl until light and fluffy. Beat in egg and vanilla extract.
Step 5
Whisk flour baking soda cream of tartar and salt together in another bowl. Stir flour mixture into butter mixture.
Step 6
Shape into 1 1/2-inch balls. Arrange 2 inches apart on prepared pans. Dip the bottom of a glass in water; then in the plate of white sugar. Press balls to flatten slightly with the sugar-rimmed glass bottom.
Step 7
Bake in the preheated oven until lightly browned 10 to 12 minutes rotating pans halfway through. Transfer to a wire rack and cool completely 10 to 15 minutes more.
Step 8
Pipe frosting onto cookies as desired making wreaths or trees.