Pistachio, White Chocolate, and Raspberry Trifle

Pistachio Cake:
1 box white cake mix
2 (3.4 oz.) pkg. pistachio instant pudding
5 large eggs
½ c. milk
½ c. water
½ c. oil
2 tsp. pistachio extract

3 (3.3 oz.) pkg. white chocolate instant pudding
6 c. milk
2 (6 oz.) pkg. fresh raspberries
½ c. shelled pistachios, gently rubbed to remove skins

For the cake: Preheat your oven to 300° and prepare two 9x13-inch cake pans with cooking spray on the bottoms and sides. In a large mixing bowl, combine the white cake mix and pistachio pudding mixes and stir with a spoon or fork until combined. Make a well in the dry mix and add all of the wet ingredients. With an electric mixer, combine all of the ingredients on low speed for 1 minute; increase the speed to medium and mix for 2 minutes. Divide the cake batter evenly between the two prepared pans, smoothing the batter until even, and place both pans in the preheated oven. Cook the cakes for approximately 35-40 minutes, or until the middle springs back when you touch it lightly, being sure to rotate the pans halfway through to ensure even baking. Allow the cakes to cool completely, and then cut them into 1-inch cubes.
While the cake is cooling, prepare the white chocolate pudding according to the package directions. Place in the refrigerator and allow it to sit while the cake finishes cooling.
To arrange the trifle, place a generous layer of the pistachio cake in the bottom of a trifle bowl, using as much or as little cake as you like. Follow the cake layer with a white chocolate pudding layer, then a generous layer of raspberries (be sure to save some to garnish the top of the trifle), and then a final layer of each of the cake and the pudding. Garnish the trifle with the reserved raspberries and shelled pistachios.