TheFork users who ate in Valencia have said really good things about Pepita Pulgarcita, ORIO Valencia Centro and SAGARDI Valencia Centro. Maybe you should give them a try!
Some of the more popular Basque restaurants having a terrace in Valencia according to TheFork users include:
ORIO Valencia Centro, with a 8.4 rating
SAGARDI Valencia Centro, with a 9 rating
Barrika Cervecera, with a 9.1 rating