Using a hand mixer, whip the heavy whipping cream until peaks form. Add the sweetened condensed milk, vanilla, and dry cake mix batter. Mix until well combined. Gently fold in half the sprinkles (about 2 1/2 T). Pour into a bread loaf pan, or other freezer safe container. Evenly sprinkle the remaining sprinkles on top. Freeze for 6 hours or overnight.
Recipe Notes
*You can optionally use your go-to "safe" vanilla or white cake mix of choice and add 1/4 C sprinkles to mix. **Great Value (WalMart brand) has a small 2.7 oz container free of all but soy, and is equal to almost exactly 1/3 C needed.