Step 1: Make the dough!
I don't have many detailed pictures for mixing up the dough, since it's fairly straight forward. Here's the recipe.
2.5 cups flour,
3/4 cups sugar, blitzed in a food processor until fine
1/4 tsp salt
two sticks of butter, cut into 1/2 inch pieces, at room temperature
2tsp vanilla extract
2tbs cream cheese, softened
Using a stand mixer, mix the dry ingredients, then add the butter piece by piece, and process until the dough looks wet and crumbly looking.
Toss in the cream cheese and vanilla, and keep going until it starts to form large clumps (30sec).
Step 2: Color time!
Anyway, add a few drops of each color and mix it in, either by hand or with the mixer. For a brown color, just add cocoa powder until it looks dark. A lot of cocoa powder will change the texture of the dough, though, so use it sparingly.
Once you have everything mixed to the color you want, wrap it in saran wrap and squish it down into disks. Place it in the fridge for a hour or two until the dough is stiff. This keeps things from getting too squishy during the cookie making process.