Whizz evaporated cane sugar in a food processor for a minute to lighten.
In the food processor or a standing mixer, combine vegan butter and process for a minute or two, until pale, light, and fluffy.
Add aquafaba and vanilla, and gently, slowly mix in the flour. Resist the urge to overbeat. Once everything comes together, boom, you’re done.
Wrap dough well. Chill in the refrigerator for two hours or up to two days. Don’t skip this step. Alternately, you may freeze dough for up to several months.
Heat oven to 350 degrees.
Line a baking sheet with a sheet of parchment or a Silpat.
Pinch off a walnut-sized piece of dough. Roll into a ball and place on baking sheet. Continue with the remaining dough, placing the balls 2 inches apart.
Create a small well at the center of each cookie. I use my pinkie finger, or sometimes, the tip of a spoon handle.
With patience, add just a dab of jam, enough to fill the indentation, but no more. This is one instance in which being overgenerous does not end well, resulting in sloppy-looking product.
Bake cookies for 10 to 12 minutes, until your kitchen is perfumed with the scent of butter and sugar. Cookies will be pale and soft, but will firm up as they cool.
Dust liberally with powdered sugar.