I looked into it briefly a few months ago but I'm not a biochemist/plant scientist; there is a lot of research on growing human organs, not so much growing fruits.
I'm sure it's possible to trick a plant stem cell into turning into a flower, then fruit, but I think the main question is whether it's economically viable. At the end of the day you would have to bypass photosynthesis and introduce sugars from some external source to grow the fruit which is probably quite expensive and inefficient. I chalked it up to being a very obvious idea which Monsato would have a solution for if it was viable.
Interesting to think though that if you did it perfectly you could turn some weight in sugar + water + stuff into an avocado.
I worry that it's not as easy as just tricking some cells into growing into what they want - you'll likely also need to replicate appropriate flow of energy, nutrients and signalling chemicals - i.e. basically fake the rest of the plant.