There is a custom to recite a special prayer when eating each of the Simanim on Rosh Hashana that alludes to that particular food. For example, when eating the pomegranate we say “May it be Your will that our merits increase like pomegranates”. The rabbis discuss the order of the blessing and the prayer. Normally, when one recites a blessing over food, one must eat it immediately so as not to cause a Hefsek, an interruption. The MagenAvraham (583:2) says that the Yehi Ratzon prayers may be recited between the blessing and the eating of theSimanim, and that this is not considered a Hefsek since there is a need for those prayers. The Ma’amar Mordechai and the Ben Ish Hai explain that it is preferable not to recite the Yehi Ratzon in this order as it may constitute an interruption.
Rabbi Yitzhak Ben Danan (LeYitzhak Reah § 200) says that the Moroccan custom is like that of the MagenAvraham. For those who suggest the prayer be said after partaking of the food, he says that it is futile since, after eating the Siman, the matter is closed so to speak. For those who suggest to say the Yehi Ratzon before the blessing over the food, this would be like advancing one’s needs before Hashem’s. It is inappropriate to ask for a good year, merits, etc. and then to bless Hashem for the foods He provides us.
Interestingly, although the common practice is to dip apples in honey, Rabbi Ben Zion Mutzafi (Shofar BeTzion) explains that honey represents Divine Judgment on a Kabbalistic level. Therefore there is a custom among some to dip the apples in sugar instead.
Summary: The Moroccan custom is to say the blessing over the Siman, then the Yehi Ratzon prayer and then to eat the Siman.