185F is too cold to properly bake a biscuit. You need to get to at least 285F to get some browning.
If you want to properly cook something in a car you need to put it on the exhaust header.
With cookies you can kind of cheat by just leaving them in there long enough to dry out the dough. Cookie dough is already highly flavored so you’re not missing much. Biscuits are just going to suck though.
