As it so happens, I had a bunch of cherry tomatoes left from an attempt at Shirazi salad. (The small tomatoes seem to be more widely available than the large ones, so they were what I used.) So I checked the cookbook, and it said you just halve the tomatoes, spread a layer of butter cake with whipped cream (it said you use only a little sugar in the cream, not even any vanilla), layer the tomatoes on, spread on more whipped cream, then put the other layer of the cake on top. Then you decorate the edges of the cream with more sliced cherry tomatoes.
Since I don't have an oven, I couldn't make their butter cake, but I got some from a local bakery I like. I had this cake with sliced cherry tomatoes and some cream I whipped.
And maybe it works better if you use the cake recipe they gave, but I have to say it was a really weird combination. Weirder than a bacon and nutella sandwich. Tomatoes have a naturally rich, heavy, sort of meaty quality to their flavor. They really felt very out-of-place with the light, sweet cream and cake.
I could imagine tomatoes as a very small component of a summer fruit dessert: maybe mostly strawberries and blueberries, with a few raspberries and tomatoes thrown in. Let tomatoes be one summer berry among many-- that's what they are, anyway. Maybe then their richness could help support the rest of the fruit flavors. Maybe skin them and make them into a sauce with the rest of them? Or maybe tomato-peach melba? Maybe just chop them and let them macerate with strawberries with a spoonful of sugar before you make them into a parfait? There's also a recipe I found online, where you blanch-peel a beefsteak tomato, then cook pieces of it in sugar before you use them to top ice cream. I feel like the tomato dessert idea has some interesting possibilities-- the one I made just wasn't one of them. I'm not giving up on that cookbook either!