1extra large sweet potatounpeeled, washed and dried (20 oz)*
⅛teaspoonDiamond Crystal kosher salt
Pierce the sweet potato with a fork on all sides. Microwave on high until very tender and the flesh is easily pierced with a fork, about 4 minutes per side. Let stand 5 minutes until cool enough to handle.
Meanwhile, in a medium microwave-safe bowl, add the butter, milk, maple syrup, kosher salt, and ground cinnamon. Microwave to heat through, 50-60 seconds. Don’t allow the mixture to boil.
On a cutting board, use your fingers to peel the cooked sweet potato. Roughly mash it with a fork right on the cutting board, then transfer the mash to the bowl with the butter mixture.
Keep mixing and mashing with a fork (or with a hand masher) until the sweet potato mash is uniform and smooth, about 1 more minute. It won't be perfectly smooth unless you use a hand mixer or an immersion blender. But I like it a bit rustic. When done mixing, I do like to use a rubber spatula to smooth it out, as shown in the video below.
*If you can't find an extra-large sweet potato, you can use two smaller ones. You'll probably need to microwave the two of them together for about 3 minutes per side, but check to make sure they can be easily pierced with a fork. They should be very tender.