Whisk baking powder, flour, and salt in medium bowl.
Whisk egg yolk, sugar, butter, and vanilla in a large bowl.
Mix dry ingredients into wet ingredients with a spatula- fold batter until dry ingredients are fully incorporated.
Place dough on floured surface or parchment paper. Sprinkle flour on top of dough- be generous and sprinkle more flour on top until the dough does not stick to the rolling pin or counter. Roll out until 1/2’’ thick.
Using a biscuit cutter or glass, cut donuts into 4’’ discs. For each disc, punch a whole in the center with your thumb and use your hands to lightly smooth out and mold the dough into a circular donut shape. Place donut on parchment paper.
Once you’ve cut out all the discs you possibly can, combine the leftover dough back together.
Repeat steps 4-6 until you’ve used all of the batter. You can also make donut holes with the dough if desired.
In a small bowl, combine the spices and sugar for the chai spice coating.
Pour canola oil into a deep heavy cast iron pot until about 2 inches deep. Heat oil until 350 degrees.
Place donut in oil and fry until light brown, about 90s per side. Immediately place back on parchment paper once done to lightly cool.
Roll donut in chai spice coating and then place back on parchment.