It was arch and annoying, and it’s not anymore. For a minute I wonder if we’ve tripped into Pleasantville, the welcome at Mix in New York is so sugary. The petri dishes have gone back to the fertility lab. The confusing prix fixe menu with its mixes of mix is no more. Chef Damon Gordon, a veteran of Alain Ducasse and Jeffrey Chodorow, is sending out fine New England clam chowder with snooty little herb-butter crackers, a pleasant-enough lobster Caesar, and splendid dry-aged steak with first-rate fries (though he’s yet to master soft-shell crab). I’d be content to make dinner of just his macaroni with ham, butter, and truffle jus. And I love the rack of lamb with its muesli crust and buttery green peas à la française set on the table in a wrought-iron pan, But please . . . $42 for three little chops? Entrées from $25 to $42 seem blindly ambitious for such a casual spot—handsome, yes, with mostly pleasant food and service verging on rude from our impatient waiter.