In a stand mixer equipped with a paddle attachment, or by using a hand mixer, blend the softened butter, cane sugar, and molasses until they are thoroughly mixed.
Scrape down the sides of the mixing bowl and introduce the egg, vanilla extract, and sourdough starter. Continue to mix until the mixture becomes light and fluffy.
In a separate bowl, sift together the flour, baking soda, various spices, and salt.
Combine the dry ingredients with the wet ingredients, gently folding them together using a spatula until a uniform dough forms.
Cover the bowl with plastic wrap or an eco-friendly beeswax wrap and refrigerate the dough for 12 hours, preferably overnight.
When it's time to bake, begin by preheating your oven to 350°F and lining a baking sheet with parchment paper. Set it aside.
Take half of the dough and place it between 2 pieces of plastic wrap. Roll out the dough to about 1/2 inch thick using a rolling pin.
Shape with your cookie cutter and carefully place the cookies on the baking sheet.
Bake the cookies at 350°F for 12-15 minutes, or until they are firm along the edges.
Once they are done baking, allow the cookies to cool completely on the baking sheet.