In a large mixing bowl, beat shortening with an electric mixer for 30 seconds. Add sugar, baking powder, baking soda and salt. Beat till combined. Bet in egg, sour cream and vanilla.
Beat in as much flour as you can with a mixer at low speed. Stir in the remaining flour with a wooden spoon. Divide in half. Cover; chill dough for 2 to 3 hours or till easy to handle.
On a lightly floured pastry cloth or waxed paper, roll each half of dough to slightly more than 1/4-inch thickness.
Cut out the dough, using a 3-inch cookie cutter. Place about 2 inches apart on a lightly greased cookie sheet.
Bake in a 350 degree F oven for 10 minutes or till edges are firm and bottoms are browned. Cool on wire racks.
Prepare Browned Butter Frosting. Frost cookies; sprinkle with decorative sprinkles or candies. Makes about 18 cookies.
In a small saucepan, melt butter over low heat. Continue heating till the butter just turns a delicate brown (don't overbrown). Remove from the heat; pour into a medium mixing bowl. Add sifted powdered sugar, milk and vanilla. Beat with an electric mixer till combined. Beat in some additional milk (1 teaspoon at a time), as needed for a spreading consistency. Add enough yellow (about 6 drops) and red (about 1 drop) food coloring to tint frosting orange. Makes about 1-3/4 cups.