Put yeast in the water with the tsp. Sugar, Let sit for 10 minutes. Heat 3/4 c water, add shortening to melt, add rest of water, sugar, salt, vinegar and egg. Add yeast mixture and 2 1/2 cups of the flour, beat until smooth, add rest of flour. Let rise until double in bulk. Make into buns and rise again. Bake 20 - 25 min. In 375 F oven