To kick things off, preheat your oven to 110°C (220°F). While that's heating up, line a large baking sheet with parchment paper. This will keep your cookies from sticking and will allow them to bake evenly.

Grab your mixing bowl and combine the room-temperature egg whites with a pinch of salt. Start beating them with an electric mixer until they froth. This is where the fun starts! It should take about 2 minutes on medium-low speed. You'll see them transforming before your eyes!

Now, it’s time for the cream of tartar. This little ingredient offers stability and helps achieve those beautiful stiff peaks we want. Add it to your fluffy egg mixture and continue mixing at medium-high speed. Watch closely until you hit soft peaks; this usually takes another 2 minutes.

Now comes the sugar-free powdered sugar! This part is key. Slowly add it in, one tablespoon at a time, while continuing to beat the mixture. This process should take approximately 3-4 minutes. As you do this, you’ll notice the glossy sheen develop, and soon you’ll achieve those stiff peaks we’re aiming for. You’ll know you’re ready when the mixture remains upright when the beater is lifted.

Next, transfer your fluffy mixture into a piping bag fitted with a star tip. This allows you to create those classic meringue shapes effortlessly. Pipe tablespoon-sized portions onto your prepared baking sheet, leaving a bit of space between each one.

Place your baking sheet in the preheated oven and let them bake for 45 minutes. After that time, turn off the oven but leave the door slightly ajar. This allows the meringues to cool inside and helps prevent cracking. Leave them there for about an hour, then remove them and let them sit at room temperature until fully cooled down.