Make one batch of sugar cookie dough. (I generally use a recipe from Alphabake A Cookbook And Cookie Cutter Set, by Deborah Pearson, but one sugar cookie recipe is pretty much the same as the next.)
Divide it in half, and add 4 tablespoons of unsweetened cocoa to one half, and 1 teaspoon of strawberry extract, with 4 drops of red food coloring, to the other (this won't add a great gob of flavor to the cookie, just a slight hint of strawberry).
Place one rectangle on top of the other.
Roll the rectangles into a tube shape, together.
Wrap the dough in wax paper, and place it in the fridge for an hour to firm up.
Remove the dough from the wax paper, and slice it into 1/4'' slices. Bake these at 350 degrees Fahrenheit, for 10 minutes, for standard pinwheel cookies.
Or, cut them into heart shapes, with a cookie cutter, before baking, for that extra Valentine's Day touch.
And, roll up the scraps of dough, and cut, for marbled heart cookie leftovers.
It's great to be a homeschooler.