Buttercream Walnut Thumbprint Cookies - Diamond Nuts

Ingredients

• 1/2 cups all purpose flour
• 1 tsp baking soda
• 1/4 tsp salt
• 3/4 cup butter, softened
• 3/4 cup light brown sugar
• 1/2 tsp vanilla extract
• 1 cup Diamond of California® In Shell Walnuts, roasted then divided
• 1/4 cup butter, softened
• 2 tbsp milk of choice
• 2 cups powdered sugar
• a few drops red and/or green food coloring