For me, part of the attraction of Huel is that it takes no time to prepare. So in that spirit I have a super-fast and convenient recommendation:
3 x scoops Huel
1 x desert spoon of smooth peanut butter (chunky gets stuck in the shaker filter).
1 x good squeeze of honey.
Shake with water to mix, as normal.
Sure, you’re adding some more calories, but you’re also adding a whole lot more flavour. And really easily, too. You sometimes end up with a bit of peanut butter that hasn’t mixed at the bottom of the shaker. But only if you’re lucky.