Preheat the oven to 350 degrees F (175 degrees C).

Mix flour, baking soda, and salt together in a small bowl.

Beat butter, white sugar, and vanilla extract together with an electric mixer in a large bowl until smooth. Add cashew butter, brown sugar, egg, and milk to the butter mixture; beat until smooth. Gradually add flour mixture and mix until just incorporated into a dough.

Roll dough into 1 1/2-inch balls and arrange onto a baking sheet. Lightly press a fork into the top of the balls to make a crosshatch pattern.

Bake in preheated oven until golden brown, 12 to 14 minutes.