My absolute favourite easy dessert is fruit with sabayon (aka zabaglione). This is deliciousness incarnate, and you probably already have most of the ingredients for it, so it's pretty easy to throw together at the last minute. My wife prefers this with blackberries, so here we go.
I've always used the recipe from The New Making of a Cook: The Art, Techniques, And Science Of Good Cooking by Madeleine Kamman, but really this recipe is a classic and is the same no matter where you get it from.
Start with a nice batch of blackberries. Around 15 blackberries/serving. Wash and sort them, and lay them out on a baking pan, while preheating the broiler in your oven on high.
4 large egg yolks¼ cup sugar
in a heavy bottom saucepan (I like to use my million year old Le Creuset that my Mom picked up at a garage sale for $5 about 15 years ago).
Heat over low heat, and never ever stop mixing. It'll start to thicken and eventually "ribbon". It took me a long time to understand this part. They say it will drip of the spoon like a flat ribbon at this stage. But the real point, is that it has thickened considerably. Once you've done this a few times, you'll recognize it. (Around this time, slip the tray of blackberries under the broiler). At this point add:
¼ cup Madeira
Really, you can add any flavouring agent here. I've even added vanilla for a friend of mine who doesn't like alcohol. But Madeira adds a really nice flavour that makes the sabayon rich and tasty.
It'll thicken again, this time pretty quickly. Pull it off the heat immediately, and continue mixing so it doesn't seize up. Meanwhile, remove the broiled blackberries from the oven (they should look like they've swelled up but not burst. Divvy up the blackberries into dishes, and drizzle a small amount sabayon on each one. Serve immediately.
The sweet richness of the sabayon makes a nice counterpoint to the bright acidity of the hot blackberries. This is delicious.