FINDSTR returns whole line data

[DeanMSands3]

Trying to pipe data into FINDSTR, but I'm getting whole lines and not the matching substrings. Have I asked this one before?
Let's say the data takes the form of

BLAH BLAH BLAH BLAH
BLAH BLAH "GOOD UNIQUE DATA"
BLAH BLAH BLAH BLAH
BLAH BLAH "SLIGHTLY DIFFERENT GOOD UNIQUE DATA"
BLAH BLAH BLAH BLAH
BLAH BLAH "MORE GOOD DATA"
BLAH BLAH BLAH

I only want the good data substrings and not the BLAHs.

EDIT: Every. Single. Time. Solution found: https://stackoverflow.com/questions/40780784/findstr-return-only-a-regex-match

SECOND EDIT: For informational purposes, I'm trying to find the most recent Volume Shadow Copy from VSSAdmin while in the Recovery Console. I'm at this point right now:
vssadmin.exe list shadows /for=C: |FINDSTR /E \\\\\?\\GLOBALROOT\\Device\\HarddiskVolumeShadowCopy.*

[pty]

Nope, FINDSTR only returns whole matching lines. You're best creating something in Powershell to return only what you want.