Having taken the bread we read that He “blessed it.” The “it” however is not in the Greek, and to understand what is meant we must remind ourselves of the prayer habits of the first century. It was customary then to begin prayer with the formula “Blessed art Thou, O Lord,” and for example one of the oldest Jewish prayer forms known to us is that called the 18 Benediction. This is a series of 18 prayers each of which begins with “Blessed art Thou, O Lord.” The form of grace before bread, as set forth in the Mishnah, runs “Blessed art Thou, who bringest forth bread from the earth” (Ber. 6:1, Danbys Translation).
When then Jesus is said to have “blessed” the idea is that He gave thanks to God in a prayer which began in the usual fashion.