Spring greens are actually young, tender cabbage plants and are sold as loose heads of thick green leaves. Spring greens do not have the hard core which is found in the middle of fully-grown cabbages. A squeaky-leaved spring green cabbage is a thing of beauty and vitality. Fragrant and nutty, this cabbage is perfect in spring, crispy salads and also great in bubble and squeak, with smoked bacon and a poached egg.