Sprinkle yeast over warm water to dissolve; let stand for 10 minutes.

In a large bowl, mix sugar, salt, eggs, butter, buttermilk, yeast mixture and 3 cups of flour together until an elastic dough forms; Mix remaining 2 cups of flour into dough, 1/2 cup at a time, until dough no longer sticks to the side of the bowl.

Remove dough from bowl and knead on a floured surface for 5 minutes.

Place dough in a large bowl, sprayed with non-stick spray, and cover with plastic wrap; allow dough to rise in a warm place until doubled in size, approximately 1 - 1 1/2 hours.

When dough is ready, turn out onto a floured surface and roll out to 1/2 inch thick.

Using a 1" round biscuit cutter or cookie cutter, cut dough into rounds and place on a cookie sheet; dip the cutter in flour before cutting dough out so it doesn't stick, and repeat with all dough; arrange dough rounds on a cookie sheet and allow to rise for another hour.

In a medium-size pot, heat 4 cups of canola oil over medium-high heat; when oil is hot, slide 2-3 dough rounds into oil using a wide spatula.

When donuts are golden brown, flip over and cook on the other side. Remove from oil when both sides are golden brown; drain and cool on a paper towel; repeat with remaining donuts.

When all donuts are cooked and cooled, fill using your favorite jams & jellies; poke a hole in the side of each donut with the handle of a wooden spoon; fill a zipper-top bag with your filling and snip the corner off to create a pastry bag; fill each donut with 1-2 teaspoons of jam; dust with confectioner's sugar and serve.