Peel and grate the carrots. Finely chop the garlic cloves. Grate zucchini, onion, spring onions, and broccoli in a food processor. Add the feta cheese and garlic to the food processor, sprinkling the corn starch on top. Mix well.
Place milk in a bowl and allow each slice of toast to briefly soak up some milk. Then squeeze each toast, allowing excess milk to drip back into the bowl, and add to the food processor.
Add eggs, vegetable broth, yogurt, breadcrumbs, and seasonings to the food processor. Mix well.
If the mixture is too soft for your liking, add more breadcrumbs to add firmness.
In a large skillet heat the re-solidified butter. Form small balls of the mixture and flatten out to make patties in the pan. Roast until golden brown on each side on medium heat.