Are there any documents written during the mission era that describe what the neophytes ate the mission ate?

In 1815 the Father President of the mission chain, Jose Senan compliled a report for the Spanish authorities that included this detailed description. At the time he was at Mission San Buenaventura.

"At the Mission there is morning prayer when the sun rises, at which time also Holy Mass is said. After sunrise they [the neophytes] are given a ration of atole [a type of cereal eaten as mush or a thin gruel], and the same is given after the recital of the Doctrina in the evening. At noon, the meal consists of pozole [a thick, hearty soup] made of wheat, corn, peas and other vegetables. Every week they receive a ration of fresh beef, in sufficient amount, according to the means of the Mission. At this mission {San Buenaventura], weekly, sixty, fifty or at least forty-five head of cattle are slaughtered.

"In seasons when the cattle are very fat, sixty head are slaughtered twice a week, in order to increase and sell the tallow and thereby procure the necessary goods [tallow and hides were traded for supplies the mission required]. The large parts of the meat are taken in carts to the fields and burnt, since there is no one to collect them and there is plenty of fresh meat in the houses. In addition, the Indians have in their homes supplies of acorns, chia seeds [taken from a plant of the mint family], fruits, zacates [an edible grass] and other various wild eatables, all of which they do not overlook, being very fond of them.

"They also eat fish, mussels, ducks, geese, cranes, quail, hares, squirrels, rats and other animals which are to be had in abundance. On account of this hodge-podge of eatables, which they have in their homes and to their being like children who eat at all hours, it is hard to determine how much they eat every day."