In an individual skillet (6.5" or 8"), placed over medium-low heat, add the butter. Once the butter has melted, add the apples and cook until soft.
Meanwhile, to make the topping, in a small mixing bowl, combine all of the dry ingredients, whisk together, then pour in the melted butter and toss to coat. Set aside.
Sprinkle the sugar, cinnamon, nutmeg, allspice, and salt over the top of the cooked apples. Add the flour and stir to coat the apples evenly. Gently pat the apples down, creating an even layer. Pour the topping on and spread evenly.
Place in the oven and bake until the topping is golden brown. This can take anywhere from 10-15 minutes. Remove from the oven and allow to cool for 10 minutes before serving.
Notes
*I like to go easy on the sugar as I prefer the apples to be a little less sweet; however, taste your apples and if you'd like them sweeter, add up to 1 additional tablespoon of granulated sugar.-If you don't own a mini cast iron skillet, you can prepare the apples on the stove in a skillet and then transfer them to mini ramekins. Pour the topping over the apples and bake according to the directions.To STORE your Individual Apple Crisp Skillet, let it cool completely, then cover and refrigerate in an airtight container for up to 3 days. You can FREEZE it by wrapping it tightly in plastic wrap and aluminum foil and storing it for up to 2 months.To REHEAT, thaw in the refrigerator overnight if frozen. Warm it in a preheated oven at 350°F (175°C) for 10-15 minutes or until heated through. Alternatively, microwave individual portions on medium power for 1-2 minutes.