The Greeks and Romans used to eat lupine seeds (it's a legume, they look a bit like edamame, but very, very, very high in alkaloids).

The simplest solution was throw them in a bag with a string and soak them in a stream for a week or two. The labor intensive solution involves boiling and rinsing them three or more times.

Legumes are good protein, but come on. Lupines do self-sow though, and you can probably get more than a cup per plant, so I expect you could be looking at an entire field of lupines and thinking it would feed your extended family for a week.