Adding color to baked gingerbread "bricks"?

Hello - I used a brick template to press bricks into my gingerbread before baking. Does anyone have any tips for how to "dye" the bricks red? AI says I can use a red gel food coloring mixed with a bit of vodka and paint it on the brick walls with a brush, but I am worried it will make the gingerbread too soft. Thank you.