Break the egg and get the egg whites. Add sugar to your egg whites and beat with clean and dry whisk or beaters until they form a firm peaks. Refer here or here
Now add almond powder, coconut, vanilla essence and using folding technique mix them well. Fill this in a piping bag and do a piping test as in notes.
Cover a baking tray with baking sheet.
Pipe the batter onto the baking sheet in rounds, leaving space between the disks. Let the piped cookies stand out at room temperature until they form a hard skin on top, about 1 hour.
Preheat oven to 325 degrees Fahrenheit. Bake cookies until set but not browned, about 20 - 30 minutes; let cookies cool completely before severing.
Piping test: Pipe a test disk of batter, about 1 1/2 inches in diameter, onto prepared baking sheet. If the disk of batter holds a peak instead of flattening immediately, gently fold the batter a few more times and retest.