Preheat oven to 350 degrees and line baking sheets with silicone mats or parchment paper.

In the bowl of a stand mixer, cream together the shortening and sugar until light and creamy, about 1-2 minutes. Mix in the egg and the vanilla extract.

Add the flour and salt and mix on low speed until completely incorporated. The dough should be slightly firm but still pliable - not sticky, and not too stiff.

Turn half of the the dough out onto floured parchment paper. Cover with plastic wrap and roll out until it's about 1/4 inch thick. Use desired cookie cutters to cut into shapes. Repeat with the remaining dough. Dough scraps can be re-rolled.

Transfer the cookies (carefully) to the prepared baking pans and bake 8-10 minutes (mine were done in 9 but it will depend on the size of your cookie cutters and thickness of your dough). Cool cookies on the baking sheet for a few minutes before cooling completely on a wire rack.

**Important: when re-rolling the dough to cut additional cookies, lightly sprinkle the parchment paper with flour ONLY AS NEEDED (you may not need to add more).

Bake cookies in batches if necessary. Cool completely before frosting.

Add the shortening, vegan butter, and powdered sugar to the bowl of a stand mixer. Mix on low speed until the sugar is incorporated. Turn the mixer to medium-high and beat for 1 minute. Mix in the vanilla extract and milk and mix until the frosting is light and fluffy, about 1 minute or less. Mix in food coloring if using.

Frost the cookies and top with sprinkles. Serve immediately or store in an airtight container until ready to serve.