LORELAI: Hey Dean. Do you want some fries?
DEAN: No, I’m actually going home for dinner. My mom made fried chicken tonight and she saved me some.
LORELAI: Oh, you have a cooking mom.
RORY: That’s so nice.
That Dean had a mother who enjoyed cooking and cooked every weekend was established months ago during That Damn Donna Reed. Much of the plot hinged upon it. Dean and Rory had a huge fight because of it. Somehow Lorelai and Rory now react as if this is fresh news that they are barely concerned about, although they still do a little passive-aggressive sniping. Perhaps they are demonstrating they have mostly moved on from that.
The Annotated Gilmore Girls 