I would recommend La Caverna. Please see directions below. It's very near to Condado, about 15 minutes tops.
Turn right out of Condado on to the RM23 heading north.
When you get to the big roundabout at the end, go straight over (think its sign posted El Palmar).
Continue straight on this road until you see a sign for Los Venterillos, and La Caverna is not far after this on the right hand side of the road. Big yellow neon sign on the actual building.
Very easy to get to and food is good.
La Caverna 639 63 37 79 or 659 25 25 05 - The owner will pick you up from Condado and drop you back off if there are enough of you.
We went there for my Dad's birthday in September, and it was excellent, although as it was a sunday lunchtime the picking up and dropping off option wasn't available. The staff were very attentive but not intrusive, and at the end were climbing up and picking big branches of grapes for us off their vines!