Take butter out of the fridge about 45 minutes before baking to allow it to come to room temperature.
Preheat your oven to 375° F (190° C).
Add 1 cup softened vegan butter, 1 cup of sugar, and 2 teaspoons of vanilla extract to a mixing bowl and beat with an electric mixer for 2 minutes until the butter and sugar are light and fluffy.
Slowly add 2 cups of spoon-measured flour, 1 tablespoon of cornstarch, and 1/4 tsp of salt to the butter and sugar mixture and beat on low until combined.
Fill your cookie press with the dough pressing it down to try to avoid air pockets.
Press the cookies onto an ungreased cookie sheet about 1 inch apart. (Hold the cookie press firmly on the cookie sheet and squeeze the lever, then pick the press straight up. The first cookie or two never come out right.)
Decorate with vegan sprinkles or sanding sugars before baking.
Bake the cookies at 375°F (190° C) for 8-10 minutes. (They will still look doughy on the top but will be slightly brown on the bottom. If you start to notice the edges turning brown, take them out of the oven immediately.)
Allow the cookies to cool on the cookie sheet before moving to a flat surface.
Notes
Vegan spritz cookies can be a little tricky since there is a big variation in the quality of vegan butter. Depending on the type of butter you use, the cookies will come out a little differently. I highly recommend a stick version like Country Crock Plant Butter, Mikayo vegan butter, or Earth Balance sticks. Tub butter has higher water content and can make the dough too soft for pressing.'
I highly recommend pressing 2-3 cookies and baking them to test and make sure that they hold their shape before pressing out a whole batch.
If your cookie dough is too soft your cookies will flatten when cooked, if this happens add 1-2 tablespoons more flour to the dough.
Be sure to spoon-measure the flour so that you have the proper flour-to-butter ratio.