For all of you cooking experts.

This weekend I decided I was going to attempt to make lemon bars from scratch.  It all went well until I cut into them and...it was all runny.  I am fairly new at the whole baking thing but would love to get better.  I have made plenty of box things but want to be able to do them from scratch.  Does anybody have a great lemon bar recipe that they love?  Or have any suggestions on how to fix the runny problem.