Cream butter with 1/3 cup flour. Pat or roll butter mixture between 2 sheets of waxed paper to form a 12x6 inch rectangle. Chill thoroughly. Soften active dry yeast in warm water. Combine milk, sugar, and salt. Cool to lukewarm. Add yeast and egg; mix well. Add 4 cups flour or enough to make soft dough. Turn out and knead on lightly floured surface until smooth and glossy, about 5 minutes. Roll dough in a 14 inch square on lightly floured surface. Place the thoroughly chilled butter mixture on half the dough. Fold over other half of dough, sealing edges well with heel of hand. Roll dough on lightly floured surface in a 20x12 inch rectangle. Fold in thirds so that you will have 3 layers. (If butter softens chill after each rolling.) Roll again into a 20x12 inch rectangle. Repeat the folding and rolling 2 more times. Chill for 1/2 hour after last rolling. To shape use 1/3 of the dough at a time. Roll in a 12x7 inch rectange (about 1/4 inch thick). Cut in strips 6 inches long, 3/4 inch wide. Hold ends of strip; twist in opposite directions. Form strip into a circle, knot, figure 8 or snail shape. Place the rolls on ungreased baking sheets. Let rise in a warm place till almost double, about 1 hour. Bake in very hot oven (450 degrees) for about 8 minutes. Add sufficient light cream to confectioner's sugar to make of spreading consistency. Add vanilla and salt; mix until smooth. Brush pastry tops immediately with icing. Serve warm. Makes about 4 dozen pastries.