Meanwhile, place the cup of vegan butter between two pieces of wax or parchment paper. With a rolling pin, flatten and shape into an 8-by-8-inch square. If the vegan butter becomes quite soft, place in the freezer for about 10-15 minutes to make it easier to work with.

Roll out the chilled dough on a lightly floured surface into a 12-by-12-inch square. Place the butter square on the top of the dough square so the corners of the butter square point to the sides of the dough square 

Fold the corners of the dough over the butter block to meet in the center and pinch edges of dough together so the seams are sealed and the butter block is completely enclosed and sealed into the dough.

If dough is very soft and vegan butter is very mushy, place on a plate, cover with plastic wrap, and place in the freezer for about 15 - 20 minutes. Roll out the dough into a 20-by-8-inch rectangle. Brush off excess flour and fold dough into thirds, like a letter.

Cover with plastic wrap and chill for 45 minutes, then move to the freezer for 15 minutes. Repeat the folder, chilling, and freezer process 2 more times.

After the dough’s final fold, chilling, and freezing, roll out onto a lightly floured surface into a 6-by-18-inch rectangle. Use a dough cutter or pizza cutter to cut the dough into three 6-by-6-inch squares and stack the squares on top of each other. If the vegan butter is feeling mushy at this point already, give it a quick freeze and come back! Roll out the stacked squares into a 6-by-8-inch rectangle. Trust me—all of this folding, rolling, stacking, chilling, rolling, stacking, folding creates those deliciously flaky layers!

Finally, cut 12 donut shapes out of the dough using donut ring cutters or a 3”-diameter circle mold or cookie cutter and 1”-diameter mold for the 'flaky donut' “hole”. Place on a parchment- or wax-paper-lined baking sheet. Cover the donuts loosely with plastic wrap and let rise in a warm place about 30 minutes. Transfer to the freezer and chill for about 10 to 15 minutes.

Meanwhile, preheat oil in a large pot or very large cast iron skillet, at least 2” deep, to 350ºF. Make your filling: in a blender, food processor, or by hand, mix together cream cheese and blackberry jam until very smooth. Place mixture in a piping bag with a long, thin tip attached, or in an injector. Make your glaze: with a fork, mix together all ingredients—powdered sugar, lemon juice, and lemon zest. Cover with plastic wrap and set aside.

Once your dough has risen and your oil is heated to 350º, begin to fry donuts, in batches. Don’t crowd! Place on a paper-towel-lined plate to cool.

Insert long, thin piping tip or injector into the side of your 'flaky donut' and fill a little; repeat this process three more times at regular intervals until 'flaky donut' is “filled”. Repeat with remaining 'flaky donuts'. Finally, glaze your 'flaky donuts': either drizzle glaze with a fork over filled 'flaky donuts' or dip tops-down in a bowl of glaze then let dry on a cooling rack. Devour!