To make the cookies, preheat the oven to 350˚ F. Grease a 13 x 18″ rimmed baking sheet . Combine the butter and sugar in the bowl of an electric mixer. Beat on medium-high speed until light and smooth, about 2 minutes. Mix in the eggs one at a time, beating well after each addition and scraping down the sides of the bowl as needed. Blend in the vanilla extract, seeds from the vanilla bean, and almond extract. In a medium bowl, combine the flour, salt and baking soda. Whisk together to blend. Add the dry ingredients to the mixer bowl and beat on low speed just until incorporated.
Transfer the cookie dough to the prepared baking sheet and press into an even layer. Bake 10-15 minutes, until light golden brown and a toothpick inserted in the center comes out clean. Transfer the pan to a wire rack and let cool completely before frosting.
To make the frosting, place the butter in the bowl of an electric mixer and beat on medium-high speed until smooth, about 1 minute. Blend in the vanilla, salt, and confectioners’ sugar until smooth, about 1-2 minutes. Mix in the milk. Tint as desired with food coloring. Spread over the bars in the pan (add sprinkles if desired), cut into bars, and serve.