1. Set racks in the upper and lower thirds of the oven and preheat to 300 degrees.

2. Use an electric mixer on medium speed to beat the egg whites and salt until whites are opaque and risen in volume. Increase speed to maximum and whip in sugar 1 tablespoon at a time. Continue whipping until egg whites are stiff, but not dry.

3. Remove meringue from mixer and fold in ground almonds, then chocolate.

4. Use a pastry bag fitted with a ½-inch plain tube (Ateco #6) to pipe the meringue. Position pastry bag perpendicular to prepared pan with tube about 1 inch above surface. Pipe a half-sphere of the meringue about 2 inches in diameter. Release pressure on tube before pulling it away sideways, to avoid leaving a point on the meringue. (If you do leave a point, use a fingertip to flatten it.) Pipe 30 meringue shells onto each pan.

5. Bake the meringues about 30 to 40 minutes, until crisp on the outside but still somewhat moist within. Slide the parchment or foil from the pans to racks to cool the meringues.

6. While the meringues are baking, make the filling. Combine the cream, butter, and corn syrup in a saucepan. Place over low heat and bring to a boil. Remove from heat and add chocolate. Shake pan to submerge chocolate and leave to melt for 5 minutes. Whisk smooth and scrape into a bowl. Allow ganache to cool at room temperature, or refrigerate briefly until it reaches spreading consistency.

7. When meringues and ganache are both cool, arrange half the meringues on a jelly-roll pan, flat side up. Whip the ganache briefly by machine until it lightens. Spread or pipe about 2 teaspoons of the ganache on each meringue and top with another meringue, flat sides together. When all the meringues have been joined, place the melted chocolate in a paper cone or in a nonpleated plastic bag. Snip end of paper cone or bag and streak tops of meringues with chocolate.