Let Rolls over-rise ever so slightly, because we want the doughnuts to be very light and full of air.
heat up the oil in the fryer or skillet to around 300 degrees F. Drop a tiny bit of dough in the oil and if it sizzles, start dropping the balls of dough into the oil. If you’re using the deep fryer, you’ll see the dough float on top of the oil. After letting it fry for a minute, flip it over with a spoon. In the fryer or on the skillet, let each doughnut fry for about a minute and a half on each side. You want the doughnuts to be golden, not brown.
After all the doughnuts have been fried, drain them on a dish lined with paper towels. Let them cool for a bit.
When they have cooled to the touch, take a small paring knife and stab a small X into the side of each doughnut, through to the middle. We are going to be using a food injector to fill the doughnuts with strawberry preserves, and pre-stabbing the doughnuts before we use the injector will go a long way toward keeping the strawberry preserves nice and neat inside the doughnut.
Spoon the strawberry preserves into the injector, place the injector “nozzle” into the incision in the doughnut and then quickly inject each doughnut with the preserves. You can use jam instead of preserves, but it will be runnier.
Place the doughnuts on a clean, dry cutting board. Grab a small hand sieve and scoop out a few tablespoons of confectioner’s sugar and dowse the doughnuts.
That’s it: Sufganiot!