Buttermilk Doughnuts

1 tablespoon dry active yeast
1/2 cup warm water
1/2 cup buttermilk
3 tablespoons shortening or butter, melted
3 tablespoons sugar
2 1/2-3 cups flour
3 teaspoons baking powder
1 teaspoon salt
vegetable oil
2 1/2 cups sifted powdered sugar
1/4 cup milk

1.Dissolve yeast in warm water in a large bowl; let stand 5 minutes.
2.Add buttermilk, shortening, sugar and 1 1/2 cup flour, baking powder and salt; mix well.
3.Add enough remaining flour to make a soft dough.
4.Turn dough onto a floured surface and knead several times.
5.Roll dough to 1/2 inch thick and cut with a 2 1/2 inch doughnut cutter.
6.Place doughnuts on lightly floured surface, cover and let rise 45 minutes or until double in bulk.
Heat 2-3 inches of oil to 375°F.
7.Drop in 4 or 5 doughnuts at a time. Cook about 2 minutes or until lightly golden in color, turning once. Drain well on paper towels.
8.Combine 2 1/2 cups powdered sugar with 1/4 cup milk, stir until smooth.
Dip each doughnut in glaze while still warm; allow excess glaze to drip off.
Cool on wire rack or serve warm