When I was in hospital after birth, I had sweet potato and butter bean cakes and I tried to replicate the recipe. I've fiddled around twice. The first time I was still on maternity leave and the recipe was for myself so I added a bit of salt and sugar. The second time I specifically wanted to make them for my daughter as a healthy finger food/snack. If anyone wants to try, this is the approximate recipe (I have no idea how much sweet potato I used):
300g sweet potato
1 tin of butter beans (drained)
a small bag of corn (or a tin)
about a cup to a cup and a half of flour
half a teaspoon of baking powder
Cook the corn and sweet potato, drain and mix in butter beans. Use a food processor or blender to purée, stir in flour, baking powder and cinnamon. Whisk in eggs. I dabbed vegetable oil onto a paper towel and spread across a baking sheet. I used a spoon and spatula to make bite size flattish portions on the sheet (batter is quite thick so doesn't spread) and baked at 180 degrees until done - was about 5 minutes per side.
NOTE: serve cold! They don't taste too great warm (almost taste raw even though it's cooked through)