Preheat the oven to 275°F. Line a baking sheet with parchment paper.
In a small bowl, whisk together the ½ cup granulated sugar and 1 teaspoon cornstarch.
Place the 2 large egg whites in a large bowl or the bowl of a stand mixer. Add ⅛ teaspoon fine sea salt. Beat the egg whites on medium speed until frothy, then increase the speed to medium-high and beat until soft peaks form, about a minute.
With the mixer running, sprinkle in the sugar-cornstarch mixture 1 tablespoon at a time. Continue until all the sugar is incorporated. Beat until the meringue reaches stiff peaks, about 3 more minutes. Fold in the ¼ cup mini chocolate chips.
Use a tablespoon to scoop 24 dollops of meringue onto the prepared tray. They should be about 1 inch in diameter.
Place on the middle rack of the oven and bake for 45 minutes for softer, chewier centers, or 1 hour for crisp meringues.
Remove from the oven and cool on the pan for 5 minutes, then finish on a wire rack. Store in an airtight container for up to 7 days.
Notes
How long should I bake meringue cookies? For cookies with a chewier inside, bake for about 45-50 minutes. For meringues that are crisp all the way through, bake the cookies for 1 hour to 1 hour and 10 minutes.
Should the egg whites be cold? For meringue, it's best to use room temperature egg whites. When the whites are at room temperature, they will whip quicker and higher, creating loftier meringue cookies.
Use a very clean bowl. For any recipe that calls for egg whites, including a gluten-free angel food cake or gluten-free angel food cupcakes, make sure that your bowl and beaters are absolutely clean and grease-free before whipping the whites.
Adaptations. You can use a little vanilla or almond extract (about ¼-1/2 teaspoon) to add extra flavor to the meringues. For a citrus burst, beat in 1 tablespoon of finely grated lemon or almond zest. For a more chocolately flavor, add 2 tablespoons of unsweetened cocoa powder.