Preheat and prep: Heat your oven to 400°F (200°C) and line a baking sheet with parchment paper. If you're using a worn-out baking sheet that's seen better days (we've all been there), maybe add a second sheet underneath to prevent burning.
Make the base: In a medium saucepan, combine water, vegan butter, sugar, and salt. Bring to a boil over medium heat. Is your kitchen already smelling amazing? Just wait.
Add the flour: Once boiling, remove from heat and add all the flour at once. Stir vigorously with a wooden spoon until the mixture forms a ball and pulls away from the sides of the pan. Return to low heat and cook for about 1-2 minutes, stirring constantly, to dry out the dough. Your arm might get tired – consider it your pre-dessert workout.
Transfer and cool: Move the dough to a mixing bowl and let it cool for about 5 minutes. Nobody wants scrambled aquafaba, trust me.
Whip the aquafaba: While the dough is cooling, beat the aquafaba with cream of tartar in a separate bowl until it forms soft peaks. This is your egg replacer magic happening before your eyes!
Combine: Gradually fold the whipped aquafaba into the cooled dough until fully incorporated. The dough should be shiny and fall slowly from the spoon.
Pipe the puffs: Transfer the dough to a piping bag fitted with a large round tip. Pipe 2-inch rounds onto the prepared baking sheet, leaving about 2 inches between each puff. Use a damp finger to smooth any pointy tops.
Bake: Place in the oven and immediately reduce the temperature to 375°F (190°C). Bake for 25-30 minutes until golden brown and puffed. Do NOT open the oven door during the first 20 minutes – your puffs will deflate faster than your enthusiasm on Monday morning.
Cool: Remove from the oven and make a small slit in the side of each puff to release steam. Let cool completely on a wire rack.