I know what you're thinking, "You must be joking!" or else, "Not my toddler!"
Hear me out. The premise of this idea came from the book Toilet Training In Less Than A Day by Nathan H. Azrin, Ph.D and Richard M. Foxx, Ph.D.
I took this route with my oldest after trying Infant Potty Training or Potty Whispering, the Every-20-Minutes-To-The-Toilet method, the Candy-Reward method, and the healthier Sticker-Reward. This method is what finally made the whole potty training thing click for her.
The basis of this method is staying positive and fully-focused on your toddler for the full 5 hours. I recommend doing this on an uncarpeted floor and in a room you can block off so that there are as little distractions as possible.
Besides this, you'll need a toddler potty, wipes, a trashcan, a child-safe floor cleaner (for accidents- and they will happen!) and paper towels, about 8 pairs of toddler underwear, salty snacks (to make them thirsty) and a sweet drink (that won't actually quench their thirst) and toys. A few of your little one's favorites and a special stuffed animal or doll that will also wear a pair of underwear.
The technique is to play with them until (every 5 minutes) their stuffed animal or doll has to go potty. You take them through the steps of going to the potty, pulling down the underwear, sitting for a few seconds and "going potty!", then they get a snack and a drink (that they actually share with your little one) and then the cycle repeats.
I recommend you read the book for full details, but this is an amazing method that I have great faith in.
I hope it works for you as well as it did for me.