Preheat oven to 350 degrees and line a baking sheet with parchment paper or silicon baking mat
In a large bowl, combine the cake mi, oil, eggs, and vanilla. Beat until combined.
Chill dough in refrigerator for about 15 minutes. This will help the dough be a little less sticky when rolling dough balls.
Scoop out 1 1/2 tablespoons for each dough ball. Roll into ball and then roll into sanding sugar or sprinkes. Place on baking sheet, flatten slightly.
Bake in oven for 10 - 12 minutes, remove from oven and let cool one minute on baking sheet before adding the chocolate heart in the center of each cookie. Remove cookies to wire rack to cool completely. The chocolate candy will harden as the cookies cool, but you can speed the process up by placing cookies into refrigerator for a few minutes.