Heat a large dutch oven or high-sided skillet over medium heat. Add the butter and allow it to melt. 

Next, add the brown sugar and stir until it has melted. 

Add the diced apple, lemon juice, and apple pie spice. Stir until the apple is fully coated with the brown sugar mixture. 

Cook for 5-7 minutes, or until the apples are just beginning to soften. 

In a small bowl, whisk together the cornstarch and water. Add the slurry to the apples and stir to combine. 

Cook for an additional 2-3 minutes, or until the filling has thickened. 

Remove the pan from the heat and stir in the chopped pecans. Allow the filling to cool completely, and then transfer it to an airtight container. 

Store the filling in the fridge for up to 1 week. This apple pie filling can be used to fill a 9” pie, as a topping for ice cream, or in a bowl with whipped cream on top!