1. PREHEAT oven to 330°F. Line a baking sheet with parchment.
2. TRACE out 1 inch circles on parchment and set this aside as a “master copy.” Reserve two extra sheets of parchment and set aside.
3. PLACE egg whites and sugar in a stand mixer bowl and fit mixer with a whisk attachment. Beat on medium low speed until egg whites start to form loose, translucent bubbles.
4. INCREASE mixer speed to medium and beat until meringue turns foamy and white and starts to resemble well-lathered shampoo, about 2 minutes. Increase mixer to high and beat until meringue holds glossy stiff peaks, about another 2-3 minutes. Turn off mixer.
5. PROCESS almond meal, powdered sugar and cocoa powder in a food processor and then sift. Add these dry ingredients to the meringue. Using a sturdy spatula fold and smash dry mixture into meringue against the bowl for about 20-25 folds.
Don’t worry about being gentle; the idea is to knock the air out. The batter should hold its shape when spooned on itself and start to slowly flatten out after about 15-20 seconds. Start checking the batter after 20 folds for readiness. Transfer batter to pastry bag and let rest for 20 minutes before piping.
6. PLACE the master copy of the drawn circles on a baking sheet and then place a sheet of parchment on top. Fill a pastry bag with batter and pipe until the batter reaches edge of circle. Remove the master copy from underneath the piped layer. Place it on a second baking sheet and pipe the remaining batter. Remove the master copy and save for future use.
7. GIVE each pan a quick hard tap against the counter, turn the pan 90 degrees and give it another quick hard tap. This will deflate any bubbles and prevent cracked shells.
8. BAKE for 15-17 minutes. Remove from oven and transfer to a cooling rack. Leave meringue shells to cool completely on the pan. Shells will cleanly peel away from the parchment when ready.
9. MAKE the blackberry filling. Place water and sugar in a small saucepan over medium heat; stir until sugar is melted. Transfer pan to wire rack to cool, 15-20 minutes. Once cooled, sprinkle gelatin on top and leave untouched for 1-2 minutes for the gelatin to bloom.
10. RETURN the pan to the stove top and over low heat stir the mixture until the gelatin bloom melts and mixture resembles the consistency of maple syrup. Remove from heat and stir the gelatin mixture into the blackberry purée. Transfer to the refrigerator to chill for 10-15 minutes or until the filling becomes thick and slightly sets.
11. ASSEMBLE the meringues. Pipe the filling onto one shell, place a second shell on top and repeat.