Cream together 1 cup of room temperature unsalted butter and 1 cup of granulated sugar until light and fluffy, about 3-5 minutes. Add 2 room-temperature eggs one at a time and then add 2 teaspoons of Rodelle vanilla bean paste.

In a separate bowl, whisk together 2 cups of all-purpose flour, 2 tablespoons of cornstarch, and 0.5 teaspoon of kosher salt. Gradually add to the butter mixture while mixing on low speed until just combined.

Divide the dough in half, wrap one half in plastic wrap, and roll out the other half to about 0.25 inch thick. Refrigerate for 20-30 minutes.

Preheat oven to 350°F (175°C). Cut out shapes from the chilled dough, place on a parchment-lined baking sheet, and freeze for 10 minutes. Bake for 10-11 minutes until edges are just set.

For the strawberry buttercream, cook 1 cup of strawberries with a splash of water until thickened for about 10 minutes. Strain and cool. Whip 0.5 cup of unsalted butter, then gradually mix in 4 cups of sifted confectioners sugar and strawberry puree. Adjust with heavy cream as needed.

To assemble, spread buttercream on half of the cookies and top with the other half, pressing gently to create sandwich cookies.