Combine all of the ingredients for cookie dough except for the food coloring. Divide the dough into three parts, add pink and purple food coloring to each and create three different colored dough.
Roughly tear up the three pieces of colored cookie dough. Cover with baking paper and roll out the dough with a rolling pin.
Cut 2 hearts with a cookie cutter for the base and top. Cut 3 more hearts and use a smaller cookie cutter to cut out the center of each cookie, leaving the outline of the heart shape. Heat for 12 minutes in the oven at 170°C.
Once cookies have cooled, with the base heart cookie at the bottom, pipe royal icing around the edge of the cookies and stack them together.
Fill the center of the cookies with strawberry chocolate, mini marshmallows, and heart-shaped candies, and cover with the top heart cookie.