Heat oven to 200C/180C fan/ gas 6. Remove the tough stems from the kale, then boil it in lightly salted water for 3-5 mins. Drain and press out the excess water.
Heat the butter in a frying pan and add the kale and garlic. Cook over a low-to-medium heat for a few mins. Season well and add some nutmeg.
Trim the broccoli and halve any thick stalks lengthways. Steam for 3-4 mins or until only just tender. Blot with a tea towel to get rid of the moisture on the surface.
Tip the kale into the base of a gratin or casserole dish and placethe broccoli on top. Season well and grate over some nutmeg. Pour thecream over, then add both cheeses. Bake in the oven for 30-35 mins or until golden and bubbling.