יְהִ֤י פִסַּת־בַּ֨ר ׀ בָּאָרֶץ֮ בְּרֹ֪אשׁ הָ֫רִ֥ים יִרְעַ֣שׁ כַּלְּבָנ֣וֹן פִּרְי֑וֹ וְיָצִ֥יצוּ מֵ֝עִ֗יר כְּעֵ֣שֶׂב הָאָֽרֶץ׃
May he be as a rich cornfield in the land upon the top of the mountains; May his fruit rustle like Lebanon; And may they blossom out of the city like grass of the earth.
Shenei Luchot HaBerit
I believe there is a profound reason why the formula chosen is one that can refer to either the future or the past. We bless the sacred bread of the past which Adam ate before the sin, and which will once again be available in the future. We have a similar discussion between Rabbi Nechemiah and the sages quoted in Shemot Rabbah, 15 where the sages quote Psalms 72,16 to prove that the word המוציא also refers to the future. The Psalmist says: יהי פסת בר בארץ, "Let abundant grain (in the shape of a piece of bread) be on earth."