Some people have mentioned adding psyllium but there hasn’t really been a recipe-topic on it so here goes!
Recently discovered psyllium husk and it honestly blows my mind: it basically transforms everything into a pudding (have tried it with protein powder too) so figured why not Huel! Ups the fibre, so don’t do this for every single Huel meal or your bowels will hate you more than they already do 
Did a Huel day today and wanted to experiment with textures.
That pudding had 30g Banana Huel + 5g psyllium husk for snack. 135kcal, 8.7g protein, 7g fibre.
Insanely voluminous and filling.
Enjoy! 
Note: Add water to psyllium to make it gel-like first, THEN add Huel in tablespoons, mixing with each addition. Otherwise the Huel’s gonna clump up; learnt the hard way.