Chocolate Chip Walnut Cookie Cake

Ingredients

• 1/2 cup (1 stick) butter, soften to room temperature
• 1/4 cup sugar
• 1/2 cup brown sugar
• 1 egg
• 1 tsp vanilla
• 1 1/4 cup flour
• 1/2 tsp baking powder
• 1/4 tsp salt
• 1/2 cup Diamond of California Chopped Walnuts
• 1/4 cup dark chocolate chunks
• 1/4 cup white chocolate chunks
• 1/4 cup milk chocolate chunks