Very often, hors d’oeuvres served at affairs include crackers with a topping such as fish, tomato, or anchovies. If one eats a cracker with a topping, must he recite two separate Berachot – one over the cracker, and one over the topping – or does he recite just one Beracha that covers both?
The Shuhan Aruch (Orah Haim 212) writes that in such a case, one recites only the Beracha of "Mezonot" over the cracker, and this Beracha covers also the topping. This follows the general principle that whenever a "Mezonot" food is eaten together with another food, the "Mezonot" food is considered the "Ikar" (primary component), and thus one recites only the Beracha of "Mezonot" over the combination, which covers both portions.
Elsewhere (in Siman 168), the Shulhan Aruch appears, at first glance, to indicate otherwise, writing that if one eats a cracker with a topping, he recites a Beracha only on the topping. However, the commentators explain that this passage refers specifically to the case of a tasteless cracker, which is eaten not for its taste, but only in order to hold the topping, so that one’s hands are not dirtied by the topping. A common modern-day example, as Hacham Ovadia Yosef writes, is a tasteless wafer cone eaten with ice cream. The cone itself has no taste, or very little taste, and it is included only to hold the ice cream, and therefore, one who eats ice cream with such a cone recites only the Beracha of "She’ha’kol" over the ice cream, and this Beracha covers also the cone. But in the case of a regular cracker which one eats with a topping, he recites the Beracha of "Mezonot," since the cracker is considered the primary component.
The Mishna Berura (Rav Yisrael Meir Kagan of Radin, 1839-1933) ruled (168:45) differently, claiming that a "Mezonot" food constitutes the "Ikar" only if it was cooked together with the other food. In his view, if a topping is placed on a cracker, then since the two products were prepared separately and are now combined, one must recite two separate Berachot, one over the cracker and one over the topping. Hacham Ovadia Yosef, however, disputes this ruling, citing proofs from earlier sources. Therefore, one who eats crackers with a topping recites only the Beracha of "Mezonot."
Summary: If one eats a cracker with a topping, he recites only the Beracha of "Mezonot" over the cracker, and this Beracha covers the topping, as well.