Preheat oven to 350 degrees. Line an 8 x 8-inch cake pan with parchment paper. Allow the paper to hang over the sides for easy removal. Set aside. Sift the dry ingredients into a large mixing bowl until there are no lumps.
Stir in the eggs, butter, yogurt, and vanilla until fully combined and a smooth dough has formed. Scrape down the sides of the bowl and form the dough into a ball. If using the flax/chia eggs allow the dough to sit for 5 minutes to absorb. Massage the ball to make sure of the texture. The dough should be smooth, moist and holding its shape well.
Place dough back into mixing bowl. Gradually stir in the food coloring until the desired color. Gradually fold in the keto chips until evenly distributed throughout the dough. Scrape down the sides of the bowl and form the dough into a ball.
Spoon the dough into the prepared cake pan. Press the dough evenly throughout the cake pan. Place in preheated oven. Bake at 350 degrees for 25 to 30 minutes or until a tester comes out clean.
Remove from the oven and allow to cool in the pan at least 1 hour to firm up. After 1 hour grasp the overhanging paper and lift the cookie slab out. Transfer to a wire rack and allow to cool completely before slicing.
Once cooled slice into desired size bars. Eat immediately or store leftovers in an airtight container at room temperature up to 5 days