OK so eating for two is a myth, but you do get some extras calories in the third trimester (300-500 depending on the source of info & presumably your size).
For lunch today I am indulging in M&S Macaroni Cheese with salad for lunch. At 720 calories I'd usually shun the Mac Cheese though I LOVE it.
For me it's a third trimester delight.
What are yours?