Yep, this little work is called
The Life and Morals of Jesus of Nazareth. Jefferson cut out and pasted passages from all four Gospels (leaving out the supernatural stuff of course) and combined them all together, in effect creating a Gospel harmony. After he completed it, about 1820, Jefferson shared it with a number of friends, but he never allowed it to be published during his lifetime for a variety of reasons; it was only first published in 1895.
As for
what Jefferson believed, he was apparently one of those “
I like Jesus but hate the Church” types. He is most closely connected with the Episcopal Church, Unitarianism, and
Deism; in fact, it may be precisely because of his sympathy for Deism that he had a rationalistic view of Jesus as moral teacher, whose teachings were unfortunately distorted by later followers, instead of incarnate Son of God.
During his 1800 campaign for the presidency, he had to contend with critics who argued that he was unfit to hold office because he did not have orthodox religious beliefs (this may also be part of the reason why he prevented publication of
Life and Morals during his lifetime, and may even be what caused him to work on it).