Fourth of July Magic: Just 3 ingredients. I throw this together when I want a festive sweet treat handled hours ahead of the backyard barbecue.

This is my easy, make-ahead Fourth of July dessert that quietly bubbles away in the slow cooker while I’m getting the yard ready and the burgers prepped. With just three ingredients, you end up with a glossy deep plum and bright white, wiggly, gelatin-style swirl that looks fancier than it has any right to. I started making this years ago when I needed something festive, kid-friendly, and hands-off for our backyard barbecue, and it’s become a little tradition—everyone peeks under the slow cooker lid to see the purple and white pools setting up.

Serve this chilled, scooped straight from the slow cooker insert into small bowls or clear cups so you can see the plum and white swirls. It pairs nicely with grilled burgers, hot dogs, and salty snacks because the cool sweetness is a nice break from all the smoky, savory flavors. Add a few fresh berries on top if you have them, or a small dollop of whipped cream for folks who like things extra indulgent. I like to set the slow cooker insert on a trivet right on the picnic table with a big spoon and some disposable cups so everyone can help themselves between fireworks and yard games.

Servings: 8

2 cups cold water, divided

Spray the inside of a 4- to 6-quart slow cooker lightly with nonstick cooking spray to help the gelatin release from the sides and make cleanup easier.

In a medium bowl, whisk together 1 cup of the cold water and the sweetened condensed milk until smooth and fully blended. This will be your creamy white layer.

In a separate medium bowl, add the plum or dark berry gelatin dessert mix. Pour the remaining 1 cup cold water over the gelatin and whisk until the powder is completely dissolved and the mixture is a deep, glossy plum color.

Pour the white sweetened condensed milk mixture into the bottom of the slow cooker. It will look thin at this point—that’s okay.

Slowly drizzle the plum gelatin mixture over the white base in a loose zigzag or spiral pattern. Do not stir; just let the colors pool and swirl naturally as they meet. This is what gives you that marbled, glossy plum-and-white look once it sets.

Cover the slow cooker with the lid. Turn the slow cooker to the WARM setting only. Let the mixture sit on WARM for 45 to 60 minutes, just until the edges look slightly thicker and a bit bubbly, and the center is still jiggly but starting to thicken. You should see some gentle steam when you lift the lid briefly.

Turn the slow cooker OFF completely. Leave the lid slightly vented for about 15 minutes to let some of the steam escape so excess condensation doesn’t drip back onto the surface and blur the swirl.

After 15 minutes, place a clean kitchen towel over the top of the slow cooker insert (not touching the gelatin), then replace the lid on top of the towel to catch any remaining drips. Let the dessert cool to room temperature, about 1 hour.

Once it has cooled to room temperature, carefully transfer the entire slow cooker insert to the refrigerator. Chill for at least 4 hours, or until fully set and firm to the touch. For best results before a backyard barbecue, I like to make this in the morning and chill it until party time.

To serve, use a large spoon to gently scoop down through the plum and white layers, keeping the swirls as intact as possible. You can spoon it into small bowls, clear cups, or onto dessert plates. Keep any leftovers covered and refrigerated, and return the slow cooker insert to the fridge as soon as everyone has been served.

For a more classic red, white, and blue look, you can use one 3-ounce box of dark cherry gelatin and one 3-ounce box of blueberry gelatin, dissolve them together in the same 1 cup of water, and you’ll still get that deep plum-toned swirl once they blend over the white base. If your crew prefers less sweetness, swap half of the sweetened condensed milk for evaporated milk; the texture will still be creamy but a bit lighter. For picky eaters who want things separated, you can pour half the white mixture into the slow cooker, let it warm and thicken slightly, then gently spoon the plum mixture down one side so they can scoop mostly one color or the other. To add a little extra fun, sprinkle red, white, and blue sprinkles over the top right before serving (do this after it’s fully chilled so they don’t melt into the surface). Food safety tips: Always keep this dessert refrigerated once it has cooled and set, since it contains milk. Don’t leave it out at room temperature for more than 2 hours (or 1 hour if it’s very hot outside at your barbecue). Make sure the slow cooker is on the WARM setting only while thickening the mixture—HIGH or LOW can get too hot and may cause curdling or an uneven, rubbery texture. Let the insert cool down before placing it in the refrigerator to avoid temperature shock and to keep your fridge at a safe temperature for other foods.