Preheat your oven to 350F and prepare two 8" round cake pans with nonstick baking spray.
Follow your instructions on the cake mix box and stir in three ounces of melted white chocolate. Divide between the two pans and bake as directed.
Prepare the Frosting
Mix the butter and shortening together for 3 minutes with a mixer. Gradually add in the powdered sugar and vanilla and only as much milk needed to make it creamy - not to stiff and not too soft.
Cover it with a damp paper towel until ready to use.
Prepare the Raspberry
Spoon ⅓ of the Lucky Leaf Raspberry Pie Filling into a fine mesh strainer. Press the glaze through the fine mesh strainer into a bowl and discard the raspberry seeds.
Decorate the Cake
Level off a cake and add a frosting dam around the perimeter of the cake. Fill the center with a half cup of raspberry filling, sprinkle on some white chocolate curls, and top with second cake. Crumb coat cake and set in fridge for 1 hour to chill.
Frost the cold cake. Tops and sides don't have to neat. Add two rows of the raspberry yogurt pretzels to the sides. The frosting will keep them attached.
Put the raspberry glaze into a baggie and snip off the corner. Drizzle the glaze around the outer perimeter. Allow it to drizzle down the sides.
Add ½ cup of frosting to a piping bag fitted with a Wilton #21 Open Star Tip and add pipe on the decorative edge. Fill the center of the cake with ½ cup raspberry filling and top with white chocolate curls.