Line a baking sheet with wax paper. Roughly chop the peanut butter cups, peanuts, caramel (if using soft caramel cut into small pieces), Starburst pieces, gumdrops and crushed hard candy into similarly sized small pieces (about 1/4 to 1/2 inch). Place each chopped component in a separate bowl so they are ready to be folded into the melted chocolate mixture.

Measure chocolate

Weigh or measure out 12 oz milk chocolate chips or chopped milk chocolate and place them in a medium heatproof bowl.

Binding & Finishing

Make candy binder

In a small saucepan over low heat combine 1 cup sweetened condensed milk and 2 tablespoons unsalted butter. Warm gently, stirring constantly, until the butter is melted and the mixture is smooth and just starting to steam (do not boil). Remove from heat and stir in 1 teaspoon sea salt. This mixture will act as a tacky binder so the assorted candies hold together.

Melt chocolate

Using a double boiler or microwave: If using a double boiler, set the bowl of chocolate over gently simmering water (bowl should not touch the water) and stir until fully melted and smooth. If microwaving, heat chocolate in 30-second intervals at 50% power, stirring between intervals until melted and smooth. Allow the melted chocolate to cool for 1–2 minutes so it isn’t hot enough to overly dissolve the small chewy candies.

Combine binder with chocolate

Pour the warm sweetened condensed milk/butter mixture into the melted chocolate and stir until completely combined and glossy. The combined mixture should be pourable but tacky — this will help suspend the chopped candies.

Fold in mix-ins

Working quickly but gently, fold the chopped peanut butter cups, peanuts, caramel pieces, Starburst pieces, gum pieces (if using) and crushed hard candy into the chocolate-binder mixture. Make sure pieces are evenly distributed. Reserve a small handful of mix-ins to sprinkle on top if you like visual contrast.

Shape and chill

Line an 8x8-inch (20x20 cm) baking pan with a sheet of wax paper or parchment leaving an overhang to lift the slab out later. Pour the candy mixture into the prepared pan and use a spatula to press it evenly into a roughly 1/2- to 3/4-inch thick slab. Sprinkle the reserved mix-ins and optional flaky sea salt on top, pressing lightly so they adhere. Chill in the refrigerator for at least 1–1.5 hours until set and firm.

Cut and store

Lift the set candy slab from the pan using the parchment overhang. Place on a cutting board and cut into squares or bars (about 24 pieces for bite-size squares). Store in an airtight container layered with parchment at cool room temperature for up to 5 days, or refrigerate for up to 2 weeks. If candy contains soft chews (Starburst, gum), refrigeration will keep texture firmer. Bring to room temperature briefly before serving if chilled.