Add the vegan butter, sugar, and vanilla extract to an electric mixer bowl and beat until light and fluffy. You could also use a regular large bowl and a hand mixer.

Add the flax egg and the molasses and blend again.

Incorporate all the remaining ingredients (except the vegan royal icing) and mix until well combined.

Divide the dough in half and roll into 2 balls. Then gently use your hands to flatten each ball into a 1-inch thick disk (about 2.5 cm), wrap tightly in plastic wrap, and refrigerate for at least 1 hour. You can also refrigerate them overnight, but in that case, let them soften on the countertop for 15-20 minutes before rolling it out.

Preheat the oven to 350ºF or 180ºC and line 2-3 baking sheets with parchment paper. 

Generously flour a work surface, as well as your hands and the rolling pin. Roll out each disc until ⅛-inch thick (about 0.3 cm). 

Using a cookie cutter, cut the dough into shapes. Then re-roll the remaining dough and continue cutting until all is used.

Bake for about 8-10 minutes or until the cookies are lightly golden brown. Be careful so they don't get burnt!

Remove from the oven and allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a cooling rack to cool completely before decorating.

Decorate the cooled cookies with the vegan royal icing (this step is optional). Decorate the cookies directly on a baking sheet so you can stick the entire baking sheet in the refrigerator to help speed up the icing setting. You can also leave the decorated cookies at room temperature to set, but it will take longer, especially during the hot months.

Serve your vegan gingerbread cookies immediately.

Keep the leftovers in an airtight container at room temperature for about 1 week or in the freezer for up to 3 months.