In what episode did Lana call Clark and watch him break into the wine cellar without him knowing that she saw everything that he did.

Season 6,Episode 16- "Promise"
It was at Lana and Lex's wedding.This is the episode inw hich Lana finds out the truth about Clarl's secret!
He tells her that he owes her the truth but Lana says he doesn't have to explain. She surprises him by admitting that she can't keep turning her back on the truth and has decided not to marry Lex. She says she will meet him at his barn at 5:00 PM, promising to be there. She hears a door open, kisses him goodbye, and ushers him out.After all Lana marries Lex.

5