Preheat your oven to 350°F. Grease a 9x5-inch loaf pan (or 2 8x4 pans for smaller loaves). Sprinkle the bottom with cinnamon sugar if desired and set aside.

In a large bowl, combine the cake mix, pudding mix (dry), 3 eggs, 1 cup water, 1/2 cup melted butter or oil and 1/4 cup sour cream. If you want it a brighter green, add in a few drops of food coloring.

Pour the batter into the prepared loaf pan.

Bake for 40-45 minutes, or until a toothpick comes out clean. Baking times may vary, so start checking for doneness around 40 minutes and adjust accordingly. If it's browning too fast, place a piece of foil over the top.

Allow the bread to cool in the pan for about 10 minutes, then remove it from the pan and transfer it to a wire rack to cool completely.

For the glaze, whisk together 1 cup powdered sugar, 2-3 Tablespoons heavy cream, 1 Tablespoon butter and 1/2 teaspoon vanilla in a small bowl. Add more milk if needed to thin.

Once bread has cooled, drizzle the glaze over top. Then sprinkle pistachios over top. Slice it into 12 servings and enjoy!