To make the dough: Using an electric mixer, cream together butter and sugar over medium-high speed until fluffy.
Add eggs one at a time mixing well after each addition. Stop and scrape the sides of the bowl periodically. Add the sour cream and vanilla. Beat on medium speed for 2 minutes.
Meanwhile, in separate bowl, sift together flour, salt and baking powder.
Lower the speed of the mixer and gradually add the dry ingredients to the creamed ingredients. Scrape the sides of the bowl, as needed. Mix just until the dough has come together.
Form the dough into one large or two medium discs and wrap the dough tightly in plastic wrap. Refrigerate for at least one hour or overnight.
To bake: Preheat oven to 375°F. Line 2 baking sheets with parchment paper.
Flour a non-stick surface and also a rolling pin. Unwrap dough and roll to about 1/3-1/2 inch thickness. Use a flour dipped 2 or 3 inch cookie cutter to cut into your favorite shapes. Place onto a baking sheet at least 1 inch apart.
Bake for 8-10 minutes or until the edges become lightly golden. Cool completely on a wire racks before decorating as desired.
To make optional icing: In a medium-size mixing bowl, mix together 2 cups powdered sugar, 1/2 tsp almond extract, 1/2 tsp vanilla extract and 1/8 cup corn syrup. Stir until sugar has dissolved and icing is completely smooth.
Add extra corn syrup up to 1/4 cup total, in small amounts until you reach the desired consistency.
Decorate cookies as desired, allowing to dry completely. Store in an airtight container at room temperature in a single layer.