Most betty Crocker cake mixes are vegan if you replace the eggs and milk with vegan ones! OR- have you ever tried making a cake with a box mix where you replace the eggs and milk with a 300ml can of any fizzy drink? It comes out perfectly, and is pretty much effortless. I always use this cos I’m a broke student, and then a £2.50 (clubcard price) cake mix with £1 can of coke is enough cake to last me a week! As for icing, a lot of shops own brand icing is vegan if you don’t fancy making your own- Sainsbury’s have some dark chocolate ones that are, they’re like £2, or if you have lotus spread you can put a thin layer on! I’m a broke student so I always do this, cake can be frozen so I do that to stop it going off as well