My daughter and I did the tea on our last trip. We both got...

Buckingham Palace - Our traditional tea sandwiches, scones and jam tarts complemented by fresh strawberries and cream, or a selection of freshly baked pastries, along with your choice of tea. $19.50 per guest

It was actually fairly filling. The scones were incredible! One of us got the strawberries, the other pastries (you get two small pasties.)

Keep in mind that it is a leisurely event. They bring the sandwiches, then the scone and tart and then dessert. So, if you want to get to MNSSHP early - and rumer has it you can enter about 4:00 PM - you might want the earlier time.