We can highly recommend El Chamo in Escalona, on the main road up to El Tiede from Los Cristianos (Junction 72). You'll need to take a big appetite however, as the traditional Canarian cuisine doesn't come small in this establishment! The bill, however, is reasonable, at roughly 45-50 euros for two courses for two, including the local fine wine. Mojo comes free here.
Even more good value - the Oasis in Adeje served the two of us a plate of salad, a huge plate of the famous garlic chicken with chips, a litre of house rose plus water, for 22 euros 47 cents!