1 y.o shoving for in mouth

She will take a handful of food and shove as much as she can fit in her mouth. I've tried spreading the food around the tray but she'll eat 5-6 pieces before she swallows. I've tried doing the one by one but she gets frustrated I've tried "slow down, 1 piece at a time but she doesn't understand. I've tried eating in front of her showing her 1 bite. If I give her a bite of let's say banana she wyill try to fit as much as she can before she bites down. Thankfully she hasn't choked but she has gaged and spit out some food. I'm really not sure what else to do. She's 16 months and has been eating independently for over 6 months now.

Any other ideas of things to try? Does it go away anytime soon?!?