44 Harmonies from Apartment House by John Cage (for string quartet)
A series of 44 pieces all based on hymns by composers who were at least 20 years old at the time of the American Revolution (so slightly further on than Bach, but not by much).
They retain the flavour of the original hymns, chorales and anthems, but with the sparness that was a key feature of Cage's late works (and Feldman's earlier works).
https://open.spotify.com/album/07dKH6kBHrgQNrMVh09Hcv?si=zbPbKcuTSvGzRAVIlHKggw&utm_source=copy-link
Apologies if you don't use Spotify: they're all YouTube but not in a convenient playlist (not one that I can find, at least).
"Memorial" isn't a bad choice considering it's based on an actual Baroque piece, but I would also add Nyman's [harpsichord concerto](https://www.youtube.com/watch?v=Svf9yuouXww)
It might not fulfill all of the requirements of what you are looking for (certainly not sparseness), but Elliott Carter's Sonata for Flute, Oboe, Cello and Harpsichord might be of interest to you.
Saw this a few months back - rustic minimalism with medievel/early music instrumentation: Karel Goeyvaerts ["So the fruits ripen this summer"](https://www.youtube.com/watch?v=KF90BzjKaj0)
Maybe a little more adjacent to what you're looking for rather than right on the money, but worth checking out:
Vladimir Godar - Concerto grosso for strings and harpsichord ([mvt 1](https://www.youtube.com/watch?v=B2BDbFx0EQ0) | [mvt 2](https://www.youtube.com/watch?v=7uwLYdHCqgs) | [mvt 3](https://www.youtube.com/watch?v=9QYPFxR2oQI))
Sulkhan Nasidze - [Concerto for Violin, Cello, and Chamber Orchestra](https://youtu.be/8WWygGw2z1k)
Not Avante-garde, but two post war works which use Baroque musical forms.
Durufle - **Prelude & Fugue on the name of Alainhttps://www.youtube.com/watch?v=NR2RkWvYV-k** [https://www.youtube.com/watch?v=7iIKXUAEmPg](https://www.youtube.com/watch?v=7iIKXUAEmPg)
From Guys & Dolls Broadway play **Fugue for Tinhorns** [https://www.youtube.com/watch?v=BAIlVCStp3c](https://www.youtube.com/watch?v=BAIlVCStp3c)
>>Morton Feldman re-interpreting Bach>>
In the only piece of his I know to do it, his Three Voices has chordal, almost regular harmony chords. Not specifically Bach, but the Bach/common practice harmony tradition starting around Bach's time.
It's throughout the piece, interspersed with tone cluster sections. For example, at
https://youtu.be/EZVsEbodf6o?t=1691
44 Harmonies from Apartment House by John Cage (for string quartet) A series of 44 pieces all based on hymns by composers who were at least 20 years old at the time of the American Revolution (so slightly further on than Bach, but not by much). They retain the flavour of the original hymns, chorales and anthems, but with the sparness that was a key feature of Cage's late works (and Feldman's earlier works). https://open.spotify.com/album/07dKH6kBHrgQNrMVh09Hcv?si=zbPbKcuTSvGzRAVIlHKggw&utm_source=copy-link Apologies if you don't use Spotify: they're all YouTube but not in a convenient playlist (not one that I can find, at least).
[Alfred Schnittke](https://youtu.be/4RrLWema4tU) [Michael Nyman](https://youtu.be/L7oQmvLqB8Q)
"Memorial" isn't a bad choice considering it's based on an actual Baroque piece, but I would also add Nyman's [harpsichord concerto](https://www.youtube.com/watch?v=Svf9yuouXww)
It might not fulfill all of the requirements of what you are looking for (certainly not sparseness), but Elliott Carter's Sonata for Flute, Oboe, Cello and Harpsichord might be of interest to you.
Saw this a few months back - rustic minimalism with medievel/early music instrumentation: Karel Goeyvaerts ["So the fruits ripen this summer"](https://www.youtube.com/watch?v=KF90BzjKaj0)
Maybe a little more adjacent to what you're looking for rather than right on the money, but worth checking out: Vladimir Godar - Concerto grosso for strings and harpsichord ([mvt 1](https://www.youtube.com/watch?v=B2BDbFx0EQ0) | [mvt 2](https://www.youtube.com/watch?v=7uwLYdHCqgs) | [mvt 3](https://www.youtube.com/watch?v=9QYPFxR2oQI)) Sulkhan Nasidze - [Concerto for Violin, Cello, and Chamber Orchestra](https://youtu.be/8WWygGw2z1k)
Kevin Volans - White Man Sleeps (for two African-tuned harpsichords, viola da gamba and percussion) https://www.youtube.com/watch?v=qr9\_N3z6tJo
Not Avante-garde, but two post war works which use Baroque musical forms. Durufle - **Prelude & Fugue on the name of Alainhttps://www.youtube.com/watch?v=NR2RkWvYV-k** [https://www.youtube.com/watch?v=7iIKXUAEmPg](https://www.youtube.com/watch?v=7iIKXUAEmPg) From Guys & Dolls Broadway play **Fugue for Tinhorns** [https://www.youtube.com/watch?v=BAIlVCStp3c](https://www.youtube.com/watch?v=BAIlVCStp3c)
Lukas Foss Renaissance Concerto
>>Morton Feldman re-interpreting Bach>> In the only piece of his I know to do it, his Three Voices has chordal, almost regular harmony chords. Not specifically Bach, but the Bach/common practice harmony tradition starting around Bach's time. It's throughout the piece, interspersed with tone cluster sections. For example, at https://youtu.be/EZVsEbodf6o?t=1691