Six months ago, I got a pedal clavier (a Hammond XPK-130G) to use with my
keyboard (a Nord Electro 5). This means I could finally start going
through the organ book I got for Christmas 2019, James Bastien's
The Older Beginner Organ Course, Level 1. In Unit 6, there's a
piece called simply "Hymn Tune," and while the melody is a bit different, I
recognized it as "Grosser Gott." Bastien notes that it's "from
'Katholisches Gesangbuch,'" which is the same origin listed for "Grosser
Gott" in The Lutheran Service Book (#940).
For my recording, I went through the piece more or less as it appears in
Bastien's book (I repeated the first two phrases, although there's no
indication to do this) and then with the melody I'm more familiar
with. I also added my own Amen cadence at the end.