Step 1

Line 2 sheet pans with parchment paper. Set aside.

Step 2

Place soft butter in a medium-size mixing bowl. Stir with a wooden spoon or sturdy spatula until nice and smooth. Add sugar and vanilla. Mix together by hand for about 1 minute, until fluffy and well blended.

Step 3

Add the flour and cornstarch. Stir until flour is incorporated and the dough is shaggy. Turn out onto a lightly floured surface and press dough in a ball. Knead a few times until fairly smooth then form into a ball again and press with your hands into a flat disk.

Step 4

On a lightly floured work surface, roll out dough to a 3/8-inch thickness. Keep work surface, dough and rolling pin lightly (not too much) dusted with flour. Cut desired shapes and place on prepared pans. Re-roll scraps as many times as needed to use up the dough.

Step 5

Place cutouts in the refrigerator for at least one hour or up to 24 hours.

Step 6

When ready to bake, preheat oven to 350˚F. Remove cookies from refrigerator and bake for 12-16 minutes or until just beginning to turn golden at the edges. Rotate pans halfway through for even browning. Cool completely before icing.

Step 7

For the mint glaze, combine powdered sugar, half and half and 1/4 teaspoon peppermint extract in a medium-size bowl. Mix until smooth. Glaze should be thick but pourable. Add a little more half and half if too thick. Taste the glaze and add more peppermint extract, if needed (see note above in post).Transfer the glaze to a shallow bowl.

Step 8

To glaze the cookies, holding onto the edge of a cookie dip the top surface into the glaze, being sure all of the surface touches the glaze. Pull cookie up and out of the glaze. Allow excess glaze to drip back into the bowl. When glaze stops dripping, quickly flip the cookie right side up and give it a gentle jiggle to allow the glaze to flow evenly over the surface. Repeat with remaining cookies. Allow glaze to dry for 15-30 minutes.

Step 9

For the buttercream piping, place butter in a medium-size bowl and stir until smooth. Add powdered sugar, 1 1/2 tablespoons half and half and mint extract and stir vigorously until smooth, adding a bit more half and half if needed to achieve a thick but smooth consistency. Add food coloring, a drop at a time, to reach desired shade of green.

Step 10

Place buttercream in a pastry bag fitted with a small round icing tip (I used a Wilton #5 round tip). Starting at the upper edge of one cookie, pipe the Christmas trees by making lines that are increasingly larger, stopping about 1/4-inch above the lower edge of the cookie (see pictures above). Immediately sprinkle with sprinkles of choice. Set aside to dry.