Preheat the oven to 350 F. Line a baking sheet with parchment paper.
Add the flour, sugar, brown sugar, cornstarch, ginger, baking soda, baking powder, salt, nutmeg, cloves, and cinnamon to the bowl of a stand mixer and whisk to combine. Add the canola oil, molasses, and milk and mix with a paddle attachment on low speed until well combined. The consistency should be at the perfect place between wet and dry. If the dough isn’t coming together when pressed together into a ball, add milk 1 teaspoon at a time until malleable like Play-Doh.
Split the dough in half. Roll the first half out onto a lightly floured surface to ¼ inch thick. Cut out the desired gingerbread people shapes and transfer to the prepared baking dish. Push the scraps of dough together and continue to roll out and cut out shapes to use all of the dough. Bake for 8-10 minutes until bottoms are just turning brown.
Repeat with remaining dough until all cookies are baked. Transfer to a cooling rack and let cool completely before frosting.
To make the frosting, add the butter and sugar to a stand mixer and beat with the paddle attachment on low to combine. Add milk as needed to loosen it up. It will become a thick enough glaze to pipe into a thin line outlining the gingerbread people. The glaze will harden as it sets, and you can set it in the refrigerator to speed this along.
Use a #3 tip or writing frosting tip, or cut off the smallest corner of a sealable plastic bag. Fill with frosting and pipe out eyes, smiles, and outlines onto your gingerbread people as you wish.