I have one gooseberry cutting that I want to propagate. Can anyone recommend a reliable mid-winter rooting method? I tried sphagnum moss last year with no luck. Thanks!

I would simply put it in the ground in the yard. I wouldn't keep it inside the house as it will make the cutting break dormancy.
Usually, I'll let a branch bend to the ground - It will grow roots while attached to the mother plant.
On my gooseberry plants, every single branch that hits the ground makes roots - even when I'm telling them not to !

The above idea (airlayering) is the best, but if you have ready made cuttings, just strip a small bit of bark on the downside end, dip in rooting hormone, and stick in  your pot. Wait till spring.

I have cuttings from 3 varieties in pots outside right now. One has even put out tiny leaves!

Gooseberries are very easy to propagate

I agree that in ground is the best and easiest way. I just received the cutting yesterday and the ground is frozen here. So my options are rooting it indoors or storing it in the fridge until spring.

Gene--what kind of soil do you use when you root in a pot?

Thanks, guys.

Just adding one more vote for the ground. I have had much luck taking a cutting during early spring when the buds are just starting to swell or barely opening, loosen some soil, put it 1/2 way in and keep it moist with a bit of shade. Actually, I haven't had one not take by doing doing that.

I just use regular store-bought potting soil, but I add to it a little sand and crushed goat manure. But I think almost any good soil would work.  Since I have limited indoor window space, I just leave mine outside, in zone 7a. I am not too worried about WHEN they leaf-out, just that they do.

Wet sand in a warm dark place is all you need. Almost 100 percent success rate.