After some experimentation I ended up with something similar to what we used to wear in Russia when I was little. Those booties are knitted and then felted. They become very thick and warm but at the same time they do not restrain the foot. The bottom is knit in garter stitch to give it extra thickness. They would work as part of the snowsuit or as slippers. This booties are made to be worn over a sock.
Materials
Peace Fleece Worsted, in color -
Violet Vyehchyeerom - 1 skein
5 DPNs size 6
safety pin