Not to be a downer here, but last year I had plenty of super large tomatoes plants - super healthy too! I got I think 2-3 flowers and 0 fruits.
But the odds are in your favor when your plants are that healthy :)
I've heard that happens when there's excess nitrogen. Nitrogen helps the green growth of plants, so I feel comfortable being more generous to herbs like basil and parsley.
If I'm guessing, you should water more to dilute the fertilizer you've already put in and/or not use too much nitrogen in the future.