1,000. The Purim Seudah
142:4 Women are also obligated to send portions to friends and to give gifts to the poor. The portions of food should be sent from one woman to another, and from one man to another. When it comes to gifts to the poor, a woman may send to a man and vice versa. Some women rely on their husbands to send for them but this is not proper; one should be scrupulous in this matter.
142:5 We are obligated to eat, drink and rejoice on Purim. Even on the night of 14 Adar, one should rejoice and have a little extra at his meal. When Purim falls on Saturday night, even though one must eat a third meal on Shabbos, he should reduce what he eats by day just a little in order to save room for a Purim evening meal. (The Mishnah Brurah does not mention reducing shalosh seudos, just that one must both have a dignified shalosh seudos and eat again at night - MB 695:3.) In any event, the meal one makes in the evening does not fulfill one's obligation for a Purim meal because the main part of the Purim meal is that it should be held during the day as per Esther 9:22, "days of celebration." One should light candles as we do on holidays even though we are having the meal during the day. We also need to rejoice a little on the night of 15 Adar. The mitzvos of giving gifts to the poor and sending portions to friends must also be done during the day. Since we are so busy by day, the Purim meal extends a little into the evening. We daven mincha early in the afternoon and make the Purim meal after mincha. Nevertheless, most of the meal must be held in the day. When Purim falls on a Friday, the Purim meal is held in the morning so as not to detract from the honor of Shabbos.
It's appropriate to learn a little Torah before starting the meal based on Esther 8:16, "the Jews had light...." The Talmud (Megillah 16b) explains that "light" means Torah. Some say that we should eat different types of beans on Purim in commemoration of the beans that were eaten by Daniel and his friends in Babylon and the beans eaten by Esther, as per Talmud Megillah 13a, "he changed her and her maidservants to the best" (Esther 2:9), meaning that they were fed beans. For the laws regarding reciting "Al HaNisim" in bentching, see 44:16-17.