dessert for around 50 people?!? help!
I don't know if you consider it too heavy, but if you can find some kind of small ramekin-shaped paper or plastic container mini tiramisus might be a hit. I just made some in 3 oz. ramekins for a small party and people were clamoring for more.
It will be less labor intensive than tartlets, and beautiful as long as you dust the top with cocoa (and stencil in a design in powdered sugar if you have the time). I would just assemble one big tiramisu and then scoop them into the ramekins and smooth out the top with extra mascarpone filling. Faster than assembling 50 tiny ones, and no one will know.
I like Pei's tiramisu idea. I'd also consider something you can easily make a lot of, like cupcakes. Or what about baklava? You can make lots of it in a big pan, then it's easy to transport.
Or maybe berry shortcakes. Make the cakes like big biscuits, then do a big bowl of macerated berries and a big bowl of cream. Good luck!
How about summer pudding?
It is basically left over bread...you can get a richer challah or other egg bread. You line a bowl, or for 50 you mihg like to do a sheet pan, then it is filled with summer fruits like berries and plums. It is topped with a layer of the bread and then wieghted down at least over night so the juice of the fruits soak the bread. When you turn the pudding out it is soaked red (if you use red berries which I would suggest).
Serve it with whip cream, creme fraiche, or even better Devonshire cream.
Tartles for 50 would be a lot of work! If you are wedded to the idea, I would do a few big tarts. I've made a large pavlova is great for a crowd. Served with freshly-whipped cream and lovely fresh berries and fruit, it always gets raves in the summer. It has the advantage that you bake the meringue on a cookie sheet, so easy to make more than one or adjust size even you don't have the largest selection of pans (actually, you could also do this with big square-shaped puff pastry tarts).
Not sure how your serving everyone, but I was recently at a gathering where they had a dessert shortcake station where people could make there own. They had strawberrys, peaches and bluberries, with shortcakes, and plenty of whip cream.
Just noticed Kagey already mentioned this idea.
You could do more than one dish to make life easy for you, and it would also mean that you could make one or two things a day (or more) in advance. Seeing as different foods have different storage needs.
This would be handy if you were cooking in your own home, and had limted space. It would also be a good way of managing the pressure.
A couple of days in advance you could do the bulk of the baking, so you could make pastry bases, cakes, coblers, crumbles and freeze.
Next day you could make any crem patissiere for fruit tarts and bake fruit off in the pastry bases, if you were going to frostor ice cakes this would be a good time to do that.
On the actual day you could get anything out of the freezer in the morning, make sure that everything is looking good by glazing fruit tarts, dressing things with berries and making sure that there is enough whipped cream and ice cream for everyone.
Phew, now I remember why I keep dinner parties down to 5 people.
If you are sold on making just one absolutely beautiful dish, I would go with making several big fruit tarts. Using a really short, and not overly sweet pastry base, with a cream patissier and then with a layer of fruit (think peaches or strawberries here) tastefully arranged. Then glaze the fruit so that they look just to good to be real.
Make Panna Cotta, very simple, very refreshing, very elegant. If you don't have 50 moulds or ramekins to plate on, just use clean individual sized yogurt cups or something like that. If you can't do that, you can always make panna cotta pie on a large shell and portion it out that way, moving plain Panna Cotta around is an exercise in frustration.
Also, infuse herb flavours (basil, thyme, mint, etc) for a hint of greennes that will help refresh the tastebuds.