need backsweetening advice

I made cider from fresh pressed apples about 7 weeks ago. Its been sitting in a corny keg secondary for the past 4-5 weeks. Its very dry and I'd like to sweeten it up so others will enjoy it for Christmas. What's the best way to do this? It will be force carbed and refrigerated. Do I need to kill the yeast before sweetening? I was thinking of adding concentrate and some honey but I don't need anything blowing up. I've read a lot of posts but I'm still unclear as to what to do.