A person who eats rice must recite the Beracha of "Borei Minei Mezonot" before eating and the Beracha of "Borei Nefashot" after. The question arises as to which Beracha – or Berachot – should be recited if a person eats rice containing small pieces of vegetables. People often serve rice with small bits of peas, green beans, or other vegetables, which, of course, generally require the Beracha of "Borei Peri Ha'adama." In such a case, must one recite "Mezonot" over the rice and "Ha'adama" over the vegetables, or does he recite only one of these two Berachot over the entire mixture?
The Halacha in this case – as discussed by Chacham Ovadia Yosef, in his recently-published volume of Chazon Ovadia (Hilchot Berachot, p. 285) – depends on which of the foods constitutes the majority of the mixture. If the mixture contains more rice than vegetables, then one recites "Borei Minei Mezonot" which covers both the rice and the vegetables. If, however, the vegetables constitute the majority, then one should recite "Borei Peri Ha'adama" and this Beracha covers both the vegetables and the rice.
This Halacha applies only if the rice and vegetables are mixed together. In cases where the rice and vegetables are served separately, then even though they are eaten together in the same meal, one must recite two separate Berachot: "Mezonot" over the rice, and "Ha'adama" over the vegetables.
These rules apply as well when one eats couscous mixed with vegetables. If the couscous constitutes the majority, then one recites "Mezonot" over the entire mixture; if the vegetables constitute the majority, then one recites "Ha'adama" over the entire mixture. Here, too, if the couscous and vegetables are served separately, one must recite two separate Berachot.
Summary: If a person eats rice (or couscous) mixed with vegetables, he recites only one Beracha: "Mezonot" if the rice (or couscous) constitutes the majority, and "Ha'adama" if the vegetables constitute the majority. This single Beracha suffices for the entire mixture, both the rice (or couscous) and the vegetables