This comes from a PBS special, My Favorite Broadway: the Leading Ladies, done in 1999. What I find striking is that for a song she's likely sung bordering on a thousand times, and something from such a distant time in her past, she gives such an affection and well-thought performance. She's not trying to re-create her days as a little kid, and she's not also trying to distance herself from her past. It's a lovely, appropriate rendition that gives tribute to her iconic song.
One of the YouTube commenters complains that she doesn't belt the number, and wonders why, saying C'mon, Andrea, you can still belt. Well -- this is why. Because she wanted to do this rendition properly. And the thing is...she does belt, just not all the way through, she picks her spots, And the result is charming. A word not generally connected with the song "Tomorrow."