Gluten-free chocolate meringue

Ingredients:

• 340g dark chocolate, broken into pieces, plus 60g chopped
• 1/2 tsp vanilla extract
• A pinch of salt
• 1 tbsp. 3% table vinegar or lemon juice
• 4 large egg whites
• 1 cup granulated sugar
• 1/2 cup chopped walnuts

Preparation:

1. Melt 340g of dark chocolate, broken into pieces, in the microwave or over a double boiler. Let cool but not harden. Stir in vanilla extract.
2. Preheat oven to 160C. Line three baking sheets with parchment paper.
3. Place salt and vinegar (or lemon juice) in the clean bowl of a stand mixer. Use a paper towel to remove any excess oil from the bowl. Also, wipe the metal parts of the whisk with a paper towel soaked in the same mixture. Do not rinse. This step is necessary to ensure the whites are fully whipped.
4. Beat the egg whites on medium speed until foamy, about 1 minute. Increase the speed to high. Slowly pour in the sugar and continue beating until stiff peaks form, about 4-5 minutes. (You can turn the bowl upside down and the meringue shouldn't fall out.) Add a third of the beaten egg whites to the melted chocolate and mix well until the mixture becomes lighter in color. Gently but thoroughly fold the melted chocolate into the beaten egg whites, then fold in the remaining 60g of chopped dark chocolate and walnuts.
5. Fill a large heavy-duty plastic bag with the meringue mixture and snip off the bottom corner, or use a pastry bag. Pipe the meringue onto the prepared baking sheets in 4 cm circles, leaving 5 cm between them.
6. Place immediately in the oven and bake for about 10 minutes. The meringue will have a glossy crust, but the inside will be chewy.
7. Let cool on the baking sheet for 10 minutes, then transfer to a wire rack to cool completely. Store in an airtight container for up to 2 days.