I have a small refrigerator & therefore a small freezer. Therefore, I cannot flash freeze food in the way that my mother taught me (to wash, spread out on a cookie sheet to freeze, & then put in a bag).
I've come up with my own way of flash freezing and maybe it will be of good use to you. I typically flash freeze veggies like onions, carrots, chiles, tomatoes (I'm not as successful with tomatoes), celery, etc. and then use them in soups, stir-fries, and omelets.
Wash the fruit or veggies you wish to freeze.
Cut them in the size you want.
Put them in a sandwich baggie that you can seal.
Mush them around so it forms a fairly flat layer.
Place the bag in the freezer. If you stack several bags on top of each other, the middle one(s) will freeze slowest.
Occasionally take the bags out and move the pieces around. This prevents them from freezing in one solid lump.
If you wait to long & they are frozen together, slam the bag on the counter to break up.
Once they are frozen (after 2-5 bag movements), they won't refreeze as a chunk.