Preheat the oven to 350 degrees. Line a small or standard sized baking sheet with parchment.
In a medium bowl, using a standing mixer or hand mixer, whip the butter, sugar and 1 tablespoon of the Rodelle Vanilla Paste together until pale and fluffy, about 5 minutes. Add in the egg yolk, reserving the egg white for the glaze. Mix just until combined before adding the flour and mixing until a dough forms.
Using a 2-inch scoop, shape 10 cookies onto the prepared baking sheet setting the cooking about 1 inch away from each other. Bake in the preheated oven for 14-16 minutes.
For the icing, mix the lemon juice with the egg white until slightly frothy. Add 2 teaspoons of the egg white mixture to the powdered sugar and remaining Rodelle Vanilla Paste. Using a whisk, mix the icing together until uniform. If the frosting is too stiff add in water 1 teaspoon at a time. The mixture should be runny but not a liquid. Whip the frosting until light and fluffy and holds its form.
While the cookies are still warm, frost each cookie with about 2 teaspoons of icing, adding the sprinkles and salt immediately. Frosting will harden in a few minutes. Serve warm or cool.
