My girlfriend really started pushing protein shakes or heavy cream to get her over her plateau. Also, at the time, we were living apart, so she just continued cooking for two, and just ate it all herself.
What works for me is gaining in 4-week cycles, followed by a 1-week break. I eat a calorie restricted diet during my break. I drink heavy whipping cream during my gaining cycles.
I was recently able to break through a plateau at 270 pounds and, during my last weigh-in, I was 283 pounds.
I've heard that one of the reasons diets fail is that dieters starve themselves and the body reacts by going into a "fat saving phase" to protect the body from starving. When the dieters go back to eating normally, the body stores fat to protect it against starving again. Perhaps cutting way back for a few days will break your plateau.
