Combine all the dry ingredients in a bowl and whisk. Add the oil, egg and vanilla and mix to combine. The dough will be thick/stiff – you can squeeze it together with your hands to bring it all together.
Roll the dough out between two pieces of parchment paper to about ¼ inch thick.
Using concentric heart-shaped cookie cutters, press out cookies in all sizes. Place on baking trays, with only 1 size per trays. Note: As the sizes change, the cooking times will also change.
Bake at 350 degrees for about 6 to 8 minutes for larger hearts and 3-4 minutes for smaller hearts. Note: cook time will be determined by the size of your heart cookie cutters and the heat of your oven, so, be prepared to monitor closely.
For all sizes, bake until just starting to brown.
Once the cookies are cooled, it's time to build your tower.
Start with the biggest heart as the base and spread a small dollop of chocolate frosting in the middle of the heart to act as "glue". Layer the cookies on top of each other. Continue to add layer after layer, using the hearts in decreasing size order.
Present on a heart-themed plate and dust with powdered sugar.
Keep extra cookies to make sweet little heart cookies, sandwich between chocolate frosting.