To prepare a very berry rhubarb bars recipe, first you need to gather your ingredients. First, you'll need the following ingredients: 1 1/2 cups fresh or frozen raspberries 2 tablespoons sugar 1 cup granulated sugar 1/4 cup butter 1 tablespoon vanilla 2 teaspoons cinnamon 1/2 teaspoon nutmeg 1 teaspoon baking powder 1/4 teaspoon salt Instructions Preheat the oven to 350 degrees F. Grease and flour 2 9-inch square pans. Line the bottom and sides of each pan with foil; set aside. In the bowl of an electric mixer fitted with the paddle attachment, cream together the butter and sugar until light and fluffy, about 2 minutes. Add the eggs and vanilla and beat until incorporated. Gradually add the flour mixture, beating after each addition until just combined. Pour the batter into the prepared pan and bake in the preheated oven for 35 to 40 minutes or until the bars are set and the center springs back when lightly touched. Allow to cool before cutting into bars.