Multiple decades have passed since John “Jack” Bogle revolutionized investing and taught us that index-like returns should be the bare minimum our clients should expect from their portfolios.

Grease and line a 30x20cm/12x8in rectangular brownie tin. Put the chocolate and butter in a heatproof bowl and put in the oven. Set the oven to 190C/170C Fan/Gas 5 (the chocolate and butter will ...