Firework Sweetness: Just 3 ingredients. I make it when I want a festive treat handled hours ahead.

This 3-ingredient slow cooker dessert is my easy, make-ahead way to add a little “firework sweetness” to our Independence Day table. A buttery golden cake base turns soft and craggy as it bakes in the slow cooker, while glossy deep violet-blue berry pie filling and bright vermilion cherry pie filling bubble up and swirl together on top. It looks like a festive, red-and-blue firework show in the crock, but it’s simple enough to throw together in minutes and let the slow cooker handle the rest while you enjoy the day with family and friends.

Spoon the warm vermilion swirl over bowls and serve it just as it is, or add a scoop of vanilla ice cream or a dollop of whipped cream so it melts into all the nooks and crannies. For a little crunch, you can sprinkle the bowls with crushed graham crackers or shortbread cookies. It pairs nicely with grilled burgers, hot dogs, and corn on the cob—classic cookout food—because it feels special without being heavy. I like to set the slow cooker right on the dessert table (set to warm) so people can lift the lid and help themselves to a steamy, bubbly spoonful whenever they’re ready.

Servings: 8

1 (15.25-ounce) box yellow cake mix

Lightly grease the inside of a 5- to 6-quart slow cooker with nonstick spray or a thin coat of butter to help keep the dessert from sticking and to encourage those soft, craggy golden edges.

Open the can of blueberry pie filling and spoon it into the bottom of the slow cooker, spreading it into an even layer. This will give you that glossy deep violet-blue base that peeks through the cake.

Open the can of cherry pie filling and dollop it over the blueberry layer in big spoonfuls. Try to leave some blueberry showing between the cherry dollops so you get a pretty red-and-blue pattern once it cooks.

Sprinkle the dry yellow cake mix evenly over the top of the pie fillings, covering as much of the surface as you can. Do not stir—leaving it layered helps create that soft, craggy golden topping with bubbling sauce pooling through.

Use the back of a spoon or clean fingers to gently pat the dry cake mix down just enough so it makes contact with some of the moisture from the pie fillings. You still want dry spots on top; those will turn golden and slightly crisp while other spots stay soft.

Cover the slow cooker with its lid and cook on HIGH for 2 to 2 1/2 hours, or on LOW for 3 1/2 to 4 hours. The dessert is done when the top looks mostly set and golden in places, with glossy blueberry and cherry sauce bubbling up around the edges and through the cracks.

Once cooked, turn the slow cooker to WARM and let it sit, covered, for about 15 minutes. This gives the bubbling fruit a chance to settle and thicken slightly while still staying hot and steamy for serving.

To serve, spoon down through the craggy golden cake to the saucy bottom so every portion gets a mix of soft cake, glossy deep violet-blue blueberry, and bright vermilion cherry. Serve warm right from the slow cooker.

For a slightly richer dessert, you can dot 4 tablespoons of butter (cut into tiny cubes) over the dry cake mix before cooking; just remember that butter would be an optional fourth ingredient. If you want an even stronger Independence Day look, you can use one can of blueberry pie filling and one can of strawberry or raspberry pie filling for a different shade of red. Picky eaters who prefer just one fruit can skip the swirl and use two cans of the same pie filling—the method stays exactly the same. For a less sweet version, choose a cake mix labeled 'reduced sugar' or pair servings with plain Greek yogurt instead of ice cream. Food safety tips: Make sure your slow cooker is in good working order and always cook this dessert on HIGH or LOW as directed with the lid on; lifting the lid repeatedly will release heat and can affect cooking time. Leftovers should be cooled to room temperature within 1 to 2 hours, then transferred to a shallow, covered container and refrigerated for up to 3 days. Reheat individual portions in the microwave until steaming hot all the way through. Do not leave the cooked dessert sitting on WARM for more than 2 hours for safety.