Pre-heat oven to 350 degrees and lightly grease all sides of a baking dish with vegan butter.
Cut apples into small chunks and add to large bowl. Add remaining ingredients for the apple filling and stir contents with a wooden spoon until well-combined. Set aside.
In another bowl, combine flour, rolled oats, brown sugar, cinnamon, and salt. By hand, fork, or pastry cutter, incorporate butter into flour/oat mixture. Mix ingredients together until your flour/oat mixture is crumbly and moist.
Spread apple pie filling evenly in a baking dish. Then, layer streusel crust evenly onto the filling. Sprinkle brown sugar on the crust if desired.
Place the apple crisp in the oven for 45 minutes to 1 hour until crust is golden brown and filling begins to bubble. Remove from oven and let cool for about 10-15 minutes. Serve warm on its own or with vegan ice cream.
This apple crisp is best when fresh. It will last in the fridge for up to 5 days. Leftovers can be frozen for up to 1 month. The crust will not be soggy! Just place the crisp in microwave or the oven at around 350 degrees until heated.