Prepare your 9x13 pan by spreading a small amount of butter on the bottom of the pan and then lining it with parchment paper. The butter just helps the parchment stay in place.
Add the sugars, the milk, and the salt to a pot on the stove or the inner pot of the Ninja Foodi. Turn the stove on medium high or the Ninja Foodi on high sear/sauté and stir the mixture to combine. Allow to heat for a few minutes to melt the sugar, while stirring occasionally.
Once the sugar mixture starts to boil, don't stir it and let it boil until the temperature reaches 239-240°F/115-116°C and then turn the heat off. This takes about 5-10 minutes.
Remove the pot from the stove or the inner pot from the Ninja Foodi and place on a heat resistant surface. Add in the peanut butter and gently stir to melt the peanut butter and incorporate it into the sugar/milk mixture. Add the vanilla extract and stir to combine.
Pour the mixture into the bowl of a stand mixer (or you can do this with a hand mixer or by hand with a wooden spoon) and use the paddle attachment to beat the fudge on medium speed for about 5 minutes. This will cool the fudge down and allow it to thicken. What I look for is the speed at which the fudge drops off of the paddle when I turn the mixer off and lift the paddle up. If it is running off quickly, you need to beat longer. It's done when the fudge is not runny, but still thin enough to pour. (see video in post for more info)
Pour the fudge into the middle of your prepared pan and spread evenly. Allow to cool for 1-2 hours. Cut into squares. Serve & Enjoy!
This recipe makes 3 pounds of fudge*** Based on feedback from several people who made this fudge and thought it was a little dry, I urge you to calibrate your thermometer and make sure it is accurate before making any candy. You can also try to decrease the cooking temperature to 235℉ instead of 239℉. Nutritional values are provided as a courtesy and thesaltedpepper.com makes no guarantees of accuracy. We do our best to ensure they are accurate, but many factors influence nutritional values that are beyond our control. Different brands of items have different nutritional values, so it is always best to do your own independent nutritional analysis based on the items you are using in a recipe if you require a high level of accuracy. Thesaltedpepper.com will not be held accountable for any errors in the displayed nutritional information.