Perhaps start the conversation by saying that you find it hard to know what to talk about with people you have never met and not wanting to sound shallow. I think you will find that many agree with you on that, which might break the ice, while others don’t mind carrying the conversation. Many like talking about themselves. Either way you have set the bar on a level you can’t really fall from. They know you think small talk is difficult.
Another strategy, is doing like everybody else. Start talking about nothing. Questions are your easiest bet.
Ask about the other persons occupation or interests. This usually opens up to an endless series of follow-up questions.
Ask how he or she know the host(s).
Ask where they live, if they like it there
Tell them what you like about the food/venue/decorations/flowers...
The weather (always works in Sweden).
You will get return questions. Answer with what you find most interesting so you can talk about it for a long time if they are interested. :)