Cream sugar and oil with your mixer, then add eggs and your vanilla extract, mixing thoroughly. Set aside.
Whisk together the flour and baking powder in a second bowl. Combine with the sugar/butter mixture in 1/3 increments.
Separate about 1 ½ cup of cookie dough into a second bowl. Mix about 10-20 drops of red gel food coloring into this cookie dough, until the color is consistent.
The cookie dough will be kind of crumbly, but turn it out onto parchment paper (parchment paper is important, so don't skip this) and work with it as-is. You don't need to dust the parchment paper with flour, the dough won't stick to it.
Roll the dough to about 1/4-inch thick.
Cut out as many little red hearts as you can manage.
Stack the little red hearts on top of each other, lining them up as best as you can, painting them on each side with egg white to “glue” them together.
Place the heart stack in the fridge while you work with the next steps.
Mix about 5-10 drops of green gel food coloring into the remaining un-colored cookie dough, until the color is consistent.
The cookie dough will be kind of crumbly, but turn it out onto parchment paper (parchment paper is important, so don't skip this) and work with it as-is. You don't need to dust the parchment paper with flour, the dough won't stick to it.
Roll the dough to about 1/4-inch thick.
Place the red heart stack into the center of the rolled-out green cookie dough.
Using the parchment paper to lift, cover the red heart stack with the green cookie dough.
If you have extra cookie dough, wrap this around the cookie roll, too.
Pour your red sprinkles across the parchment paper and roll your cookie dough in the red sprinkles, attempting to cover the whole roll.
Place this in the refrigerator, wrapped in the parchment paper for 2 hours or overnight.
Preheat the oven to 350-degrees. Prepare a baking sheet by lining it with parchment paper. Set aside.
Remove the cookie dough roll from the fridge and slice it into ¼-inch thick slices. If you need to, you can “touch-up” the hearts a little with a damp finger.
Place cookies on the baking sheet 2 inches apart (although they will not rise or expand).
Bake cookies for 10 minutes.
Remove and allow cookies to cool completely.