Hello and welcome to DC! I often make my brownies a little underdone, I like em the same way as Pdswife, and often have the same problem with getting them from the bowl into the pan without 'loosing' a bunch on the way!
If you had just cooked them I would say pop em back in the stove for a couple more minutes. If they have long since cooled, I am not sure there is much you can do to fix the problem.
Just remember when baking them to test with a toothpick before taking them out of the oven or shutting the oven off. If it comes out clean, they are done. If it comes out with just a little on it, perfect in my book, and if it comes out with a lot on it, needs more cook time. Just go a couple of minutes at a time until they are done the way you like them. If they are just a little underdone and you go five minutes, you could end up overcooking them, that is why I go two minutes at a time until they are just the way I like them.