Heat a medium-sized saucepan over medium heat. Toast the teff, stirring frequently, for 3-6 minutes. To the toasted grains, add 1 ½ cups of the water, cinnamon, nutmeg, and 1 tablespoon of the butter. Reduce the heat to a low boil and cook, covered, for 10 minutes.
Meanwhile, place a small saucepan over medium-high heat. To the pan, add the remaining butter. Place the apple in the melted butter. Cook the apple until soft, about 3 minutes. Add the remaining water to briefly steam the fruit, then add the maple syrup and stir to coat the apples. Remove the from the heat and set aside.
After the teff has cooked for 10 minutes, remove the lid from the pot and stir in the salt, coconut milk, vanilla extract, and stevia. Reduce the heat to low and cook the mixture uncovered, stirring occasionally, for another 5-10 minutes.
Serve the teff porridge warm with the apple compote over top.