I’m all in favour of picnic dinners and these burgers are as good as the view.
A handful each of;
Brazils…(a combination of three or whatever you fancy.)
Leave in a bowl just covered with warm water for half an hour or more.
Drain and put into a food processor and chop
Add diced white onion, a handful of breadcrumbs, two or three big dollops of tomato paste, pepper, salt, pinch of chilli, teaspoon of cumin. Whizz.
Pop in fridge for an hour. Make into wee balls or patties and bake on an oiled tray for ~10 mins or until brown and flip.
Take somewhere nice to eat!