I'm going to try my hand at making ribollita as a first course for 12 people and have been studying a number of recipes. I want to make an all vegetable version, such as this one from Lidia Bastianich.
One interesting version ended with the leftovers of the reboiled bread soup fried like hash in a skillet with copious quantities of olive oil for a fourth meal.
I'll use all cavalo nero (dino kale aka black cabbage), if I can find some locally, instead of a mix of chard and kale. What other suggestions and tips do you have?