Muster Cookies Or Muster day Cookies (From the Encyclopedia of Cookery, a modern adaptation of a recipe from Hanna Glasse.) 3/4 cup shortening. 1/2 cup firmly packed brown sugar 2 eggs 1 teaspoon vinegar 1 1/2 cups unsifted all purpose flour 1/2 teaspoon each ground cinnamon and ginger. 1 1/2 teaspoons baking soda 1/2 teaspoon salt 3/4 teaspoon baking powder 3/4 cup molasses 3/4 teaspoon water. Cream shortening and sugar until light and fluffy. Beat in eggs one at a time. Stir in vinegar. Sift dry ingredients. Add to the first mixture alternately with the molasses and water. Drop by teaspoons 2 inches apart on a greased cookie sheet. Bake in preheated moderate oven (350 degrees F) for 8 to 10 minutes makes 8 to 10 dozen cookies.