Preheat oven to 180°C.
Melt the butter and olive oil in a fry pan over LOW-MED heat. Add the diced onions and fry gently for 8-10 minutes, or until softened. Add crushed garlic plus 1 teaspoon of Herbes de Provence.
Add the sourdough to bowl of a food processor and, using short bursts, cut the bread to get a variety of coarse, fine and chunky crumbs.
In a bowl, add the breadcrumbs, nuts, lemon zest, 1½ teaspoon of Herbs de Provence, and parsley and then mix to combine.
Beat two eggs and pour over the mixture to coat all ingredients with the egg, add salt and pepper to taste and combine.
Spoon into oiled mini muffin tray, push down slightly and top up, or simply roll into balls. Cook for 25 minutes or until golden brown, leave in the tray to cool slightly before removing them.