First, in a glass measuring cup, combine the warm water, sugar, and yeast. Whisk them together and let the mixture sit for about 5-10 minutes. It should become foamy, which means your yeast is active and ready to go.
In a separate medium-sized bowl, measure out your bread flour. Add the salt and the activated black charcoal powder to the flour. Stir these dry ingredients together until the charcoal is evenly distributed, creating a uniform gray color.
Attach a dough hook to your stand mixer. Pour the activated yeast mixture and the dry ingredients into the mixing bowl. Mix on medium speed for about 5 minutes, adding the black tahini as it combines to create a smooth, black dough.
Place the dough into a clean bowl and cover it tightly. Let it rise in a warm spot for about 60 to 90 minutes, or until it has doubled in size. The warmer the room, the faster the dough will rise.
Roll the risen dough to a ¼-inch thickness on a floured surface. Use a small 1 ½-inch biscuit cutter to cut out as many circles as you can. For taller buns, stretch and tuck the edges under each circle. Place them on a lined baking sheet, brush with nondairy milk, sprinkle with sesame seeds, and bake at 400°F for 7-9 minutes.
While the buns cool, prepare the veggie burgers. If frozen, defrost them first. Use the same 1 ½-inch biscuit cutter to cut out small circles from the larger veggie burger patties. You can cook these mini patties in an air fryer at 400°F for 7-8 minutes or bake them in the oven at 425°F for 12-15 minutes until heated through.