To replace them I found this lovely pattern on Ravelry: I Heart Cables provided for free by Justyna Lorkowska.
Unfortunately Jakob doesn't like the pompom so I had to omit it but knit a tiny little point instead.
Since there were many comments that the pattern runs very large I figured I can try knitting it in DK weight yarn instead of worsted. In terms of width this worked well but the hat turned out way too short. So I tore back to the ribbing and added two of the first cable repeat sections. Now it's a tiny bit high but he loves it and I think he looks very cute - but of course I am his mom :-)
For the point I decreased to 6 sts (vs 12 in the original pattern) and knitted about 6 rows, then pulled the yarn through the sts and wove in the end.
I used selvedge sts on the ear flaps to give them a finished look.