In a medium mixing bowl, whisk cake flour, cornstarch, baking powder and salt together. Set aside.
In a large mixing bowl, using a hand mixer, cream butter and sugar together until combined.
Add in egg, vanilla and almond extracts.
Stir in sour cream and mix until well blended.
Add in dry ingredients and mix until just combined, using a rubber spatula to scrape down the sizes. Do not over mix. Cover with plastic wrap and chill for a minimum of 60 minutes.
Preheat oven to 350℉. Line a baking sheet with parchment paper.
To portion out the dough, scoop about 3 Tablespoons out, dust hands with powdered sugar, and roll into a ball.
Place on a baking sheet, about 3 inches apart.
Flatten with the bottom of a glass or flat measuring cup, dipped in powdered sugar. Cookies should be between ½” and ¼” thick.
Bake for 9-11 minutes; rotating the baking sheet halfway through. Cookies should be just lightly golden - NOT BROWN. Cookies will continue to bake on the cookie sheet while cooling. Cool completely before frosting.
For frosting, beat butter for 1-2 minutes, or until it has lightened in color and is creamy.
Add in the powdered sugar, vanilla, salt and heavy cream, a Tablespoon at a time, until the desired consistency is reached. Add food coloring to tint, if desired.
Frost cookies, leaving a small rim of the cookie exposed. Top with sprinkles or jimmies.
Notes
You can use any color food coloring that you like.
Any sprinkles can be used.
The dough needs to chill for at least 60 minutes.
These cookies can be frozen, see my tips above.
These can be made smaller to make more cookies, again see tips above.