I just found a really good way to get rid of a large mound of spinach, chard or beetroot greens, in the old vegetable book that lives in my house.
You need the greens, half that weight of mushrooms, a clove of garlic, butter, oil, breadcrumbs, grated cheese, and egg yolk. 3 egg yolks does enough for 1 kg of greens (!) and that volume barely fills a 4-person casserole dish. It shrinks a LOT.
Wash the greens and chop them, and parboil them.
Chop the mushrooms into chunks, and the garlic clove, and fry them in the butter until the mushrooms are a bit brown. While this is happening, oil an oven dish and throw breadcrumbs on the inside. Turn the oven on to gas mark nut burgers*
Then stir in the greens, without the water they were parboiled in. Now take it off the heat.
Next, put in the cheese, and let it melt. The recipe says ricotta but I didn't have any so I used cheddar, and oddly it worked.
Then, put in the egg yolk and stir like a crazy person so it doesn't cook in lumps - you want cheesy goo with greens and mushrooms.
Pour it into the oven dish and put it in the oven for 30-45 minutes, it will come out lovely.
*gas mark nut burgers: my oven doesn't have settings on it anymore, because it is that old (rented house) so having found out what setting to do nut burgers on, I measure everything in relation to gas mark nut burgers. I think that must be about 200 degrees C or gas mark 7.