Sentence:  they shal have [...] every <WSD>mease</WSD> of two dishes, one with pottage & boiled meate, the other roste (if it be no fasting day.) And if it be a fish daye, then they shal have two like <WSD>meases</WSD> of white meate & fish. 
Meaning of the word marked with <WSD> tags:  A mess, a mese: a meal.