Though unconventional, one of our favorite meals during our trip was lunch at
Mac Dario in Panzano in Chianti. About 45 minutes west of Montevarchi. (Is that where you are staying? The one that I'm looking at is about 35 km SE of Firenze -- not SW of Firenze.)
If going to Montalcino, consider going about 10km south for the
Gregorian chants at the Sant'Antimo Abbey.