Bake until a tester inserted in the center comes out clean, 45-55 minutes. Cool 10 minutes. Turn the pan upside down onto a serving plate; remove pan. Allow the cake to cool completely, about 2 hours.
Place the chocolate chips in a heatproof bowl. Heat the cream in a small saucepan until simmering, then pour over the chocolate chips. Allow to sit for 5 minutes, then stir until smooth. Drizzle the glaze over the cooled cake. Drizzle the caramel over the cake, sprinkle on the chocolate chips, toffee pieces and chopped candy bar. Store loosely covered at room temperature.