I need to bring in a 'healthy' dessert for my son's preschool class--no nuts, and prep needs to be relatively simple. Any suggestions?

I make this 101Cookbooks recipe anytime I have a cookie craving. Simple, delicious and pretty healthy. You can also vary it by adding dried fruits (or subbing them for the choco) or anything, really. I usually do almond pieces and dried cherries, I also sub steel cut oats because I just like a funkier, crispier texture. http://www.101cookbooks.com/archives/nikkis-healthy-cookies-recipe.html

if it isn't prohibitive to use plates and forkss, how about baked apples served at room temperature? just chop up some apples into big chunks, cover with a mix of brown sugar, oats, cinnamon, maybe a little butter, and bake until soft. it would be easy to do the night before and let cool before serving.

Oatmeal cookies would be good. You can cut the sugar of most recipes by almost half and still have something delicious and pleasantly sweet. Coconut gelatin dessert with fresh fruit on top would be good (I don't know if you have an asian market around, but the agar-agar based coconut dessert mixes are generally pretty delicious). You could also make your own flavored gelatin desserts using juices and/or purees, that way you could control the amount of sugar being added.
I'd probably just make fruit salad with a yoghurt and honey dressing though, 'cause I'm lazy.

How about this great, great chocolate bark, sans chili, pistachios and cashews, if they are a problem?
http://www.food52.com/recipes/2105_ancho_chilicinnamon_chocolate_bark

What kid doesn't love chocolate and dried fruit?

kids love the fruit kebabs. Seems very sophisticated to them especially if you use a good variety of fruit.

Healthy is a relative term...rice crispy treats really aren't so bad. They have sugar, but no fat. Depending on how you feel about jello, knox blox (super charged jello, its finger food) are also not terrible and loads of fun.

For that matter, I sometimes do candied popcorn with jello (just cut the peanuts...http://www.kraftrecipes.com/recipes/jell-o-rainbow-popcorn-54804.aspx). Again, some sugar there, but limited fat and if you juice it with a bit of extra food colouring, you can get some fantastically silly colours!

My son has a life-threatening peanut allergy and was also in class with a child with celiac disease; we found trays of strawberries, cut up and speared with toothpicks, accompanied by a dip made of vanilla yogurt with a bit of honey/agave added was always a hit!

Along the kebab train of thought, I think that age loves anything with a toothpick -- strawberries, pineapple cubes, orange sections. Play with your food works.

If there are no dairy issues in the class, why not bring in some plain low-fat yogurt that you've stirred up really well with an all-natural jam or fruit preserve (there are great no-sugar-added or corn-syrup-free brands out there!). You could bring some add-ins like chopped dried fruit, fresh fruit, a decently healthy cereal, crushed animal crackers or graham crackers, etc. and let kids choose a topping.

And I always thought "healthy dessert" was an oxymoron.

Not sure if your "no nuts" includes nut butter. If the nut butter is ok...I like to do these 5 min / 6 ingredient what I call "good for you" rice krispy treats: Rice Crisp Cereal, Almond Butter, Vanilla extract, Cinnamon, Brown Rice Syrup, Cacao Nibs.
Heat up the almond butter, syrup, vanilla and cinnamon. Stir in rest. Shape into golf balls, freeze for at least 10 min. They are always a hit.

When our daughter was in Montessori classes, we had to provide snack once a month. One of their favorites was fruit kebabs. The other favorite was sweet shortcake biscuits with flavored butters. They loved using the little spreaders to make their own "sandwich". Our daughter (now in college, home for the summer) just came in and I asked her if she remembered any of the snack/desserts and her eyes lit up and she said, "remember the fruit sushi we made? It was so cool!". We used unsweetened. puffed rice cereal and fruit leathers from Trader Joes, cut apple or orange julienned strips rolled inside with blackberries and raspberries on top as "roe" , Swedish Fish (not healthy but cute)

I meant fruit - not fruity. Sorry for the type.

This is a great recipe that caught my eye: http://dashandbella.blogspot.com/2010/03/berkeley-bloggers.html. It's sort of a yoghurt parfait with granola and caramel. You could add berries to something similar, and layer it in a roasting pan, like a sweet lasagna! Cut out the caramel if healthy REALLY means healthy, or sub honey. I'd like it, at least... What sort of dessert did you have in mind - cookies, cake, etc? my other idea is a good banana or similar bread. I've had an amazing prune bread made with, of all things, baby food. It very desserty, but we had it for breakfast. You could make them into muffin 'cupcakes' if you wanted.

I remember those days! Thanks for being a great Mom! Take a mixture of fruity - maybe grapes, strawberries, rasberries, blueberries - whatever your son loves the most - put in little bags and tie them with a ribbon. If your son is into stickers, have him put one on each bag. Then you simply hand them out. Pre-schoolers love color and unwrapping things.