Deignan was too strong for Banks in a sprint to the line with Italy’s Consonni finishing third.
“I’m really happy and grateful to the whole team for their effort,” Deignan said.
Dutch Marianne Vos, Italy’s Noemi Cantele, and Britain’s Emma Pooley have all won the event twice.
Back on the roads where she triumphed in 2015 and 2017, it was the first victory for former world champion Deignan.
Banks make the winning move, attacking with 35km of the 101km race remaining, with Trek-Segafredo’s Deignan one of three riders to bridge over before the set went clear.
Deignan added: “It’s been a difficult season for everybody so far and we’ve had a lot of bad luck in the first few races.
“It’s been clear to me that we’ve had the strongest team in all the races and finally the luck was on our side.”
Deignan and Banks are now both due to compete for Great Britain in Thursday’s European Road Championships.