If you eat all the large leaves now you will probably starve the plants and prevent the growth of the buttons because there will be too few leaves for good photosynthesis. . Try to be patient. When the buttons are big enough for picking you could take perhaps one leaf at a time from each plant but by then the sprouts will be nicer than the leaves. If you wait until there are no more sprouts and the crop is about finished you can eat the leaves then if you want to...

I agree with Yorks. in the spring any unharvested sprouts start to grow and they make a lovely leaf veg too.

welcome to GoY too.

Yes you can eat the leaves of brussels sprouts. They are brassica and taste similar to cabbage or collard greens and can be prepared the same way. Just be sure to first wash them real good if you don't want a little extra protein - bugs.

Come spring once sprouts have all been eaten, sprout tops make very useful "Spring Greens"

As mentioned, I would let the plants make their own height which will be dependant on the variety and not harvest the leaves. The contention always was that you should make the soil compact around them to stop them from 'blowing'. The Brussels' tops should be eaten when the sprouts have finished producing in the spring.

Just had a thought - if you want leafy greens at this time of year try kale (another year as its too late now...)If you get half a dozen plants you can take a leaf from each and you can go on like that all winter.