Wash the lemon with hot water, remove peel, squeeze out the juice. In a saucepan pour water, add salt and lemon juice, bring to a boil and blanch the florets and cauliflower slices 10-12 minutes. Discard in a colander and dry. Wash the parsley, shake, grind. Melt the butter, add the breadcrumbs, ground coriander and fry, add the parsley and zest, stir again. Add to the mix the cauliflower, stir and serve.