Moses
Deuteronomy 10:4ESV·traditional attribution

And he wrote on the tablets, in the same writing as before, the Ten Commandments that the LORD had spoken to you on the mountain out of the midst of the fire on the day of the assembly. And the LORD gave them to me.

Matthew Henry Presbyterian @wholebiblehenry

There were four things in and by which God showed himself reconciled to Israel and made them truly great and happy, and in which God's goodness took occasion from their badness to make him the more illustrious: - I. He gave them his law, gave it to them in writing, as a standing pledge of his favour.

Commenting on Deuteronomy 10:1-11

John Gill Reformed Baptist @doctorgill

And he wrote on the tables according to the first writing,.... The same laws, in the same letters: the ten commandments which the Lord spake unto you in the mount; in Mount Sinai, on which he descended, and from whence he delivered the decalogue by word of mouth in an audible manner, that all the people could hear it: out of the midst of the...

Jamieson-Fausset-Brown Reformed @jfbcommentary

he wrote on the tables, according to the first writing--that is, not Moses, who under the divine direction acted as amanuensis, but God Himself who made this inscription a second time with His own hand, to testify the importance He attached to the ten commandments.