I already know that it is forbidden to make a bracha on a stolen lulav (SA OC 649:1). However, i'm not sure if this also applies to making a bracha on stolen food. The difference seems to be that by a lulav, the bracha is on the mitzvah, which is being done with something forbidden. By food, the bracha is on your benefit (ברכת הנהנין), so it's possible that you might make a bracha on benefiting, even if it came to you in a non-permissible way.
So: should a bracha be made on stolen food?
The Mishna Berurah (196:4) says that if someone steals wheat, grinds it and bakes it, it is actually a Machlokes on whether he could say a Bracha on it. Nonetheless, from the Mishna Berurah it's clear that the Machlokes applies because in this particular case, the thief effected a change (שינוי) through which he acquires the item. However in a "standard" case of stealing it would appear that everyone agrees it's prohibited to say a Bracha.
The Laws of Brachos (page 144) indeed says:
One who steals food, or even takes food without the owner's permission (or without being certain that the owner approves), may not recite a b'racha.
However, he does bring the above opinion from the Mishna Berurah in the footnotes ("... some authorities require that a b'racha be recited").
No -- a bracha should not be made on stolen food.
The gemara in Sanhedrin 6b paskens that if someone would steal wheat, grind it, and bake bread out of it, a bracha still would not be made on that bread.
The Rambam (Hilchot Brachot 1:19) brings this as the halacha -- any food that is asur does not get a bracha either before or after.
(Credit to this answer for pointing me to the gemara source, which pointed to Rambam.)
