What Brocha does one say before and after eating rice cakes?
The Brocha Reshona is Ha’adoma.
The Brocha Achrona is Borei Nefoshos.
Even though when eating rice, since there is a doubt regarding the Brocha, one should eat them in a Seuda (or make a Brocha on a piece of Mezonos and Ha’adoma), there is a distinction between rice cakes and rice, because rice cakes are not cooked but rather puffed and therefore they wouldn’t be Mezonos (Seder Birkas Hanehnin 1:8).
If you want to be Machmir, you can also make a Brocha Shehakol on another food – and have in mind to cover the rice cake.
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See also:
Do rice cakes need bishul yisroel? If so Is it safe to assume kosher company brands are?
Rice cakes do not pose a Bishul Yisroel concern, as their “puffing process” is not considered “cooking.”
See also here:
https://asktherav.com/does-my-cereal-need-to-be-pas-yisroel/