Hi
It is cold – but not wet – and I am looking for winter gloves that are like ski mitts but that you can open up to let some air in when you heat up after a couple of hours. Any recommendations?
Thanks!

Can’t think of any. Just wear ski gloves with vents?

Are you actually somewhere that is properly cold?

Unless its a hard frost/subzero I just use my standard riding gloves, knowing that I will be OK when I get warmed up.

It is around zero for at least an hour after sunrise. I am wearing something like these:
https://www.btwin.com/en/cyclist-equipment/winter-cycling-gloves/19928-700-winter-cycling-gloves-neon-yellow.html
They are warm enough but there is no venting 🙁

Silk liner gloves under your riding gloves, take the liners off when you warm up.

I can’t ever think of a time when my hands have been too hot in winter.

Layers. Along the lines of the Dissent 133 or the Assos system.

Second pair of gloves in your pack or jersey pocket.

I think Polaris Hoolie have palm vents