You can heat treat flour and cake mix in the microwave or oven (see note 2). Test the flour and cake mix to ensure it’s reached a safe temperature of 165°F. Let flour and cake mix cool completely to room temperature before using. Don’t use any burnt or clumpy flour or cake mix (if it’s off-color or smells burnt, it is most likely burnt). The flour and cake mix should be light, white, and fluffy. Spoon the cooled flour and cake mix into a measuring cup and level the top with the back of a table knife. (If you press and scoop either the flour or cake mix into a measuring cup, you’ll have too much).
Once the heat-treated cake mix and flour have completely cooled, add the (spooned and leveled) cake mix, flour, baking soda, and salt to a medium bowl. Stir and set aside. (While we aren’t baking this dough, the baking soda gives it an authentic flavor; leave it out if desired, just don’t forget the salt!)
In a bowl with a stand mixer attached (or use a hand mixer) beat the room-temperature butter and beat until smooth and creamy, about 2 minutes. Add granulated sugar and light brown sugar and beat until combined. Beat on medium speed for 3–4 minutes until mixture becomes slightly fluffy and very light. Add heavy cream and vanilla and mix until combined.
Add the dry ingredients right on top of the wet ingredients. Add the white chocolate chips and sprinkles right on top. Beat until just combined; do not overmix. Use a spatula to scrape the sides of the bowl as needed. If the dough is at all dry, add a bit more heavy cream; if it is wet, add a tablespoon or 2 more of the heat-treated cake mix.
Stir in any desired mix-ins and enjoy! I love this dough freshly made, chilled, or even frozen!
Notes
Note 1: Optional add-in suggestions: milk chocolate chips, dark chocolate chips, M&M’s, marshmallow fluff, extra sprinkles, and coconut.Note 2: Heat treating the flour and cake mix:
Heat treat in the microwave: Put the cake mix and flour in separate microwave-safe bowls. I recommend heat treating more flour and cake mix than the recipe calls for (1/2 to 1 cup extra) to be sure you have enough in case some burns or clumps. Microwave the bowls separately in bursts of 30 seconds, stirring between each burst. Take your time, stirring well to make sure none of the flour or cake mix burns. Use a thermometer to test them in a few places to make sure each has reached 165°F throughout.
Heat treat in the oven: Preheat the oven to 300°F. Line a large sheet pan (with sides) with a nonstick liner or parchment paper. Spread the flour on the pan (treat more than you’ll use; 1/2 to 1 cup extra). Bake the flour, removing and stirring it every 1 and 1/2 minutes. Every time you remove the flour to stir, test it with the thermometer. As soon as it reaches 165°F, it’s safe. Repeat on a separate tray for the cake mix until it reaches 165°F.
Storage: Store leftovers in an airtight container in the fridge for up to a week. Let it sit at room temp for a few minutes before enjoying again.