Make the base: Line an 8-inch square baking pan with foil, extending it over the sides. Put the butter in a medium heatproof bowl; position the bowl over a saucepan of barely simmering water (the bowl should not touch the water). Once the butter melts, stir in the sugar and cocoa. Whisk in the egg; cook, whisking, until the mixture is warm and the consistency of hot fudge, 6 minutes. Remove from the heat; mix in the saltine crumbs and peanuts. Press the crust into the pan. Set aside the saucepan of water.

Make the filling: Spread the jelly over the crust in the pan; place in the freezer for a few minutes. Beat 5 tablespoons plus 1 teaspoon butter, the peanut butter and confectioners' sugar with a mixer until light. Spread over the jelly layer; return to the freezer while you make the glaze.

Place the chocolate and the remaining 2 tablespoons butter in a heatproof bowl; set over the pan of simmering water and stir until the chocolate is melted. Remove from the heat; stir until smooth. When cool but still runny, spread the glaze over the chilled peanut butter layer. Freeze for another 30 minutes.

Use the foil flaps to remove the bars from the pan; cut into squares while still cold. Serve cold and keep leftovers refrigerated.

Photograph by Kate Sears