Proof the yeast. Warm the milk to 105°F. Stir in the yeast and 2 tablespoons of the sugar. Let sit for 5 minutes, until frothy.

Mix the dry ingredients. In a large bowl, whisk together the flour blend, psyllium husk powder, baking powder, salt, and the remaining sugar.

Make the dough. Add the milk mixture, melted butter, and eggs to the dry ingredients and mix well into a soft dough. Psyllium absorbs roughly 10 times its weight in liquid, so expect to add most of the extra warm milk — add it a tablespoon at a time until the dough is soft and pliable but not sticky.

Form the dough into a ball, cover, and refrigerate for 1 hour. (The chill firms up the psyllium gel, which makes the dough easier to roll and cut.)

Heat the oven to 200°F, then turn it off to create a warm proofing spot.

Place the dough on flour-dusted wax paper, press it down slightly, top with a second sheet of wax paper, and roll to 1/2 inch thick. Cut out circles with a biscuit cutter and set them on a plate.

Cover the donuts loosely with plastic wrap and let rise in the warm oven with the door cracked open for 1 hour.

Pour about 3 inches of vegetable oil into a large pot and heat to 350°F.

Fry the donuts one at a time, without overcrowding the pot, for about 3 minutes per side, until deep golden brown. (Psyllium doughs can brown a touch faster — keep the oil at 350°F and adjust the heat as needed between batches.)

Lift out with a slotted spoon and drain on a paper towel–covered plate.

Let the donuts cool completely. Poke a hole in the side of each with a skewer and pipe jelly inside using a piping bag fitted with a small round tip.

Roll the filled donuts in powdered sugar and serve immediately.