• Combine the softened butter and sour cream in the bowl of a stand mixer (or a large bowl if mixing by hand). Pour in the sugar and cream them together, beating for several minutes at medium speed until light and fluffy. Add the egg and the two vanillas and mix well.
• In a separate medium bowl, combine the flour, baking powder and salt. With the mixer on low, gradually pour the flour mixture into the butter mixture until it is well-combined and results in a soft dough.
• Divide the dough into two balls, then flatten them to about 1-inch thick discs and refrigerate them, wrapped in plastic wrap, for at least one hour or up to three days.
• When you're ready to bake, preheat the oven to 350 degrees Fahrenheit.
• Take the first disc and roll it out to your desired thickness, ideally between sheets of parchment paper which will prevent the dough sticking to your rolling pin or counter. I also prefer a slightly thicker cookie, so I'd recommend around 1/4-inch thick dough (which will rise a bit further during baking).
• Cut out cookies into your desired shape(s) and place them about 1-inch apart on a parchment-lined cookie sheet. Then pop them back in the fridge for about 10 minutes before placing in the oven.
• Bake for 8-12 minutes, depending on the size and thickness of your cookies. Keep a close eye, when you start to see a tiny golden edge at the bottom, remove from the oven and place on a cooling rack. After five minutes, transfer the cookies to the cooling rack directly.
• Make sure your cookies are completely cooled before you decorate them, as the icing will melt off the top otherwise. Store in an airtight container, with wax or parchment paper between layers IF cookies are iced, cookies without icing can be stacked directly on top of each other.

Icing

• To make the icing, simply combine all the ingredients in a small bowl and mix with small whisk or a fork. You may need to add more water (or more powdered sugar) to achieve your desired consistency. As you decorate the icing may start to dry out, but just add a few drops of water and stir to revive it. Divide and add colors as you wish. Have fun and enjoy!