Sweet Packet Party: Just 4 ingredients. My sister makes these mini foil-wrapped treats and stacks them like bricks so everyone goes crazy guessing what gooey surprise is hidden inside.

These slow cooker 4-ingredient butterscotch blondie packets are my kind of party trick: simple, cozy, and just a little bit mysterious. My sister started making these mini foil-wrapped treats years ago for family game nights, stacking them in the slow cooker like shiny little bricks so everyone could guess what gooey surprise was hiding inside. They’re perfect when you want a warm dessert without turning on the oven, and the slow cooker keeps them soft and melty until everyone’s ready to dig in.

Serve the warm foil packets straight from the slow cooker, using tongs to place one on each plate so everyone can unwrap their own little surprise. They’re lovely on their own, but even better with a scoop of vanilla ice cream, a dollop of whipped cream, or a glass of cold milk. For a fun family night, set out small bowls of toppings like chopped nuts, mini marshmallows, or chocolate chips so folks can sprinkle them over the gooey blondies after unwrapping.

Servings: 8

1 (15.25-ounce) box yellow cake mix

Tear off 8 small sheets of aluminum foil, each about 8x8 inches. Lightly spray the center of each piece with nonstick cooking spray or rub with a tiny bit of butter to help prevent sticking. Set aside.

In a medium mixing bowl, combine the dry yellow cake mix, butterscotch chips, melted 1/2 cup butter, and milk. Stir with a sturdy spoon until everything is well blended. The mixture will be thick, somewhere between a cookie dough and brownie batter.

Divide the blondie mixture evenly among the 8 foil squares, placing a scoop in the center of each. Gently press or spread the mixture into a rough rectangle or square, about 1/2 inch thick, leaving at least 1 inch of foil border all around so you can seal them.

Fold each foil square up and over the blondie mixture to create a snug packet: bring two opposite sides together and fold down to seal, then crimp the other two sides tightly so no batter can leak out. You want little brick-shaped packets that can be stacked.

Place a folded kitchen towel or a few layers of paper towel in the bottom of a large slow cooker if you’d like to protect the surface from any sharp foil edges (optional, but helpful). Arrange the foil packets in the slow cooker in a single layer, then stack remaining packets on top like bricks, alternating direction slightly so they fit snugly.

Drizzle the remaining 2 tablespoons melted butter over the tops of the foil packets. This gives that shiny, buttery finish and a little extra richness as they warm.

Cover the slow cooker with the lid. Cook on LOW for 2 to 2 1/2 hours, or until the packets feel set but still soft when you gently press them with tongs. They should feel like chewy blondies, not firm cake.

Turn the slow cooker to WARM if you’re not serving right away. Keep the lid on so the packets stay soft and gooey until everyone is ready to eat.

To serve, use tongs to lift out the packets and place them on plates or a tray. Let them sit for a minute or two so no one burns their fingers, then let each person unwrap their own foil packet to reveal the gooey butterscotch blondie inside. Enjoy warm, as is or topped with ice cream or whipped cream.

For picky eaters, you can swap the butterscotch chips for semi-sweet chocolate chips or white chocolate chips while keeping the rest of the recipe the same. If you’d like a slightly less sweet version, use only 3/4 cup butterscotch chips and add a small pinch of salt to the batter to balance the sweetness. To make a fun guessing game, mix and match chip flavors in different packets—some butterscotch, some chocolate—and let everyone guess what they got before unwrapping. For a nutty twist, sprinkle a few chopped pecans or walnuts on top of the batter before sealing the foil (just remember this if you’re serving anyone with allergies). If you don’t have yellow cake mix, a butter or vanilla cake mix works just as well. These packets are best eaten warm the day you make them, but leftovers can be cooled, kept in their foil, and refrigerated; reheat gently in the slow cooker on WARM or in a low oven until soft again.