Two summers on, and the New Zealand international is hoping to serve up a twocourse special that will be the highlight of his footballing career.
For starters, the budding chef is looking forward to representing his country in South Africa, as the All Whites make only their second appearance at a World Cup finals.
Then, for mains, the 28-year-old striker is keen to turn his current loan deal at Middlesbrough into a permanent transfer from Celtic.
The ingredients for success are all in place; now it is down to Gordon Strachan to decide whether Killen's attributes are to his taste.
I'd love to stay at the club, and hopefully I will, said the Kiwi, who put his culinary skills to the test this week as part of a community initiative at the Shaw Trust in Stockton.
But I think they want to assess which players are going out first before they start to think about who they want to bring in.
That's down to the manager's discretion. I have a great summer ahead of me with the World Cup, and it would be a great double if I could play in South Africa and then come back and sign for Middlesbrough.
Since leaving Parkhead in January, Killen has made 14 starts and two substitute appearances for the Teessiders.
His three-goal return is somewhat disappointing, but his work rate, combined with an ability to lead the line and bring others into play, has compensated for a failure to fire in front of goal.
Tellingly, Killen has generally been preferred to Lee Miller, who arrived in a permanent transfer two weeks after his team-mate, and Strachan appears to have been impressed by his impact alongside fellow Antipodean Scott McDonald.
I would like to have scored a few more goals, said Killen, who will play opposite Mc- Donald when New Zealand take on Australia in their opening World Cup warm-up match on May 24.
But when I haven't been scoring goals, I'd like to think I've still been contributing, and that's massively important.
Like the rest of his teammates, Killen struggled to make much of an impact last weekend, as a 2-0 defeat at West Brom killed off any hopes of a play-off place.
Strachan branded the performance at the Hawthorns an embarrassment, and coming off the back of an eight-game unbeaten run, Killen admits the manner of Boro's surrender was difficult to take.
Things were going fairly well and we were becoming strong, resolute and hard to beat, he said. We'd become a bit of a force at home as well, which was good, so it was really disappointing to go out on that note.
Killen was also on the losing side in this week's charity cook-off, but that hasn't stopped the former Manchester City trainee eyeing a future career in the kitchen.
Cooking is something I really enjoy doing, he said.
I've always done it. I love to cook and, when I finally retire from football, I'd like to have my own restaurant.
The guy who edits Celebrity Masterchef knows I like cooking, so he rang me up and asked me to go on the show. I said I'd love to, thinking it would only mean going down to London for a couple of days. Unfortunately, you have to make yourself available for the whole of July, so my preseason training with Hibs meant I wasn't able to do that.
I didn't really think I could ask the manager for a month off to do a bit of cooking!