Try this Kitchen Sink No Bake Cookies recipe, or contribute your own.
Granulated sugar does the structural heavy lifting in no-bake confections. When boiled with butter, milk, and cocoa powder, sugar undergoes a critical phase change. Heating this mixture forces the sucrose to dissolve completely into a supersaturated solution. Boil the mixture for precisely one minute over medium-low heat. Exceeding this timing drives off too much moisture, yielding crumbly, dry cookies that refuse to hold their shape on the tray. Undercooking leaves excess water behind, preventing the sugar crystals from reforming properly upon cooling.
Unlike baked cookies dependent on flour proteins, no-bake structures rely on cooling fat and sugar crystallization to solidify. Stirring in rolled oats, peanut butter, pretzels, and chopped peanuts introduces varying moisture levels and structural density. Fold the mini marshmallows in last. Doing so prevents them from melting entirely into the hot base, preserving distinct pockets of sweetness and chew. Drop the batter onto waxed paper while still warm. Work efficiently because the cooling fat stiffens rapidly once removed from the heat source.