It seems that Debian Buster has some problems with Kubernetes. While this base setup is working, one should also assure that every tool uses the legacy iptables. If not, pod's will not be able to reach the kubernetes api... And then... failure all over!
So we also need:

update-alternatives --set iptables /usr/sbin/iptables-legacy
update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy
update-alternatives --set arptables /usr/sbin/arptables-legacy
update-alternatives --set ebtables /usr/sbin/ebtables-legacy

```

I got it working. Seems like the podCIDR wasn't set. Setting it manually by patching the nodes worked for me:

for node in master node-1 node-2 node-3 do 
  kubectl patch node $node -p '{"spec":{"podCIDR":"10.96.0.0/12"}}'
done

Not sure if this is a problem with the recipe, or if this is a bug in kube-router/kube-controller-manager. Anyway, If have my cluster up and running now!!!

I'm going to have a look into it!
Thanks and hopefully I'll find the cullpritt, so the recipe can be updated with some nice new ingrediënts