In a large mixing bowl, whisk egg whites with an handheld electric mixer or stand mixer on low-medium speed until it becomes frothy like cappuccino foam and you start to see faint "trails" in the meringue created by the mixer.

Add granulated sugar one tablespoon at a time while continually mixing on medium speed. Ensure sugar is dissolved between each addition, about 10-15 seconds.

When all the sugar has been added, whisk on high speed until meringue reaches stiff peaks and feels silky smooth when rubbed between your fingers.

Sprinkle cocoa powder on top of the meringue and fold in with a rubber spatula until combined. 

Transfer meringue to a piping bag fitted with a large open star tip. 

Put a dab of meringue under each corner of the parchment paper to prevent it from sliding around while piping.

With the piping tip at a 45 degree angle to the baking sheet, squeeze out a blob of meringue. Slowly release pressure when the blob is your desired size and pull away from the blob while angling the piping tip to be 90 degrees  to the baking sheet to make the "tail" of the heart.

Repeat with the other half of the heart by starting the blob half and inch beside the first blob and ending the tail by joining it with the first tail.

Sprinkle meringue hearts with sprinkles.

Bake for 40-45 minutes or until meringues can be lifted off parchment paper cleanly and meringues are not sticky to the touch.

Turn off the oven and leave meringues inside with the oven door slightly opened until completely cooled.