For folks who did not like the scene the way it was written, directed, and acted, I offer the alternative fanfiction scenarios. Please feel free to choose a response you would like better.
Scenario One:
Blaine: I love you.
Kurt: (Spews coffee all over Blaine, himself, and the table, and then knocks the coffee over in his excitement. The two boys gather napkins and begin cleaning up the mess.) I'm sorry, I'm sorry! I'm sorry! (he says in a high pitched squeal, two octaves higher than normal.) I love you too!
Blaine: Remind me not to say romantic things to you when you have your mouth full.
Scenario Two:
Blaine: I love you.
Kurt: (While swallowing his coffee, snaps his fingers. Instantly, the boy band of Puck, Sam and Artie come out to serenade Blaine with a reprise of Bella Noche.) I have just been WAITING for you to say that. See, I came prepared. I love you, too.
Blaine: Well, I can do better than that. (Snaps his fingers. The Warblers instantly materialize. Blaine gets up to join them and they begin to sing that classic love song from their hit album, Do You Think I'm Sexy. )
Kurt: Oh, yeah? Well, I can do better than that. (Snaps his fingers. All of New Directions appear in their competition outfits. Kurt goes and joins them. They begin to sing an original song that Kurt wrote for Blaine, which would have been the showcase song if Finn had not kissed Rachel. Kurt begins to sing) "Ooooooh Blaine, you drive me insane...."
Blaine: (Snaps his fingers. The Mormon Tabernacle Choir appears.)
And so forth.
Scenario Three:
Blaine: I love you.
Kurt: I love scarves.
Scenario Four:
Blaine: I love you.
Kurt: Sam and I eloped while we were in New York.
Blaine: Then why he is over there holding hands with Mercedes?
Kurt: I am gonna cut a bitch.
Scenario Five:
Blaine: I love you.
Kurt: (Gets down on one knee.) Blaine Warbler, I have a proposal for you. Will you.... join the Glee Club?
Blaine: I've always wanted to do a big Broadway number...
Kurt: No, those are mine.