Rashi on Exodus 16:23/רש"י על שמות ט״ז:כ״ג

1את אשר תאפו אפו THAT WHICH YOU WOULD BAKE, BAKE whatever you wish to bake (cf. Onkelos: די אתון עתידין למפא and Rashi on אז ישיר משה) in the oven bake to-day — all that you will need for two days; and what you require to boil of it in water boil to-day. The expression baking applies to bread, (cf. Rashi on Genesis 40:1) and the expression boiling to a cooked dish.

2למשמרת means as something put by (to be kept).