What is the preferred action on this flop?? Wasn't at the table long, but table was fairly tight passive.

sb 20.60
bb 34.05
utg 25.00
utg1 27.05
Hero 23.50
btn 27.00

utg posts 0.25

Dealt to Hero 7s5s
utg checks, hero raises to 1.10, btn calls, folds

Flop: 3s6c6s pot 2.80
Hero bets 2.80, btn raises to 5.60...[/list]