Preheat the fryer. In a mixing bowl, dissolve the yeast in the water, for about 2 to 3 minutes. Set the yeast aside in a warm, draft-free place for about 10 minutes, or until the yeast bubbles up and the mixture almost doubles in bulk. In a mixing bowl, combine the sugar, shortening, salt, and blueberries. Stir in the boiling water. Using a fork, lightly mash the blueberries against the side of the bowl. Cool the mixture to 110 degrees F. Stir in the cream, yeast mixture and egg. Add 2 cups of flour and blend well. Stir in the remaining flour, 1/4 cup at a time until the dough is smooth and not sticky. If the dough becomes to stiff to stir easily with a spoon, work in the flour with your fingers. Turn the dough out onto a floured surface and pat the dough into a rectangle about 1-inch thick. Lightly dust the surface of the dough with flour. Roll out the rectangle to at least 25 inches long by 10 inches wide and about 1/4-inch thick. With a sharp knife, cut the dough into 10 five-inch square beignets and deep-fry them immediately. Fry the beignets, a couple at a time until golden brown and crispy on all sides, about 3 to 5 minutes. Remove the beignets from the oil and drain on a paper-lined plate. Sprinkle the beignets with powdered sugar and serve.