Preheat & Prep: Preheat your oven to 200°F (100°C). Line a large baking sheet with parchment paper. (A tiny dab of meringue under each corner stops the paper from sliding!)

Start Whipping: Pour the aquafaba, vanilla extract, and cream of tartar into the spotlessly clean bowl of a stand mixer (or use a hand mixer). Fit the whisk attachment.

Add Sugar Slowly: Begin beating on high speed. Once the mixture is foamy, start adding the sugar very slowly, one spoonful at a time, while the mixer is running. This is key to a stable meringue.

Whip to Stiff Peaks: Continue beating for a total of 6 to 6.5 minutes. You are done when the meringue is thick, glossy, and holds stiff peaks (when you lift the beater, the peak stands straight up and doesn't curl over).

Pipe or Dollop: Transfer the meringue to a piping bag with a tip (or just use a spoon). Pipe or dollop 1-inch mounds onto the prepared baking sheet, spacing them about 1 inch apart.

Bake Low & Slow: Bake for 1.5 to 2.25 hours (90-135 minutes). Rotate the pan halfway through. The meringues are done when they are dry, light, and easily lift off the parchment.

Test for Doneness: To check, remove one meringue, let it cool for 60 seconds, and taste it. If it's crisp to your liking, they're done. If it's still sticky or chewy inside, bake for another 15 minutes and check again.

Cool & Store: Once baked, turn off the oven and let them cool completely on the baking sheet. Store immediately in a completely airtight container in a cool, dry place.