Grease baking pan with 1 tsp of butter and set aside.
Dice or shred apple and mix into apple butter.Set aside.
To make the crust
Mix oats, oat flour, date sugar, salt and cardamom in a bowl.
Add cold butter into the dry ingredients. Coat the butter in the dry mixture and with your fingers pinch the butter into small pieces. Keep working the butter into the dry ingredients until it's broken down into small pebble-like pieces and all the dry ingredients have been coated in the butter. Do this step fairly quickly so you don't melt the butter.
Stir in the cold water, 1 tablespoon at a time, to moisten the dough. You want the dough to hold together when squeezed in your hand.
Scoop out ½ cup of the dough and put into the fridge.
Press remaining dough into a greased baking pan. Create an even layer, getting all the way to the edges.
Bake the crust for 5 minutes to set.
Remove the crust from the oven and spread the apple mixture over the top in an even layer.
Get reserved dough from the fridge and crumble on top of apple mixture.
Bake at 350 for 15 - 18 minutes, until crumble topping is lightly browned.
Remove baking pan from the oven and let cool for 15 minutes.
Cut bars into your preferred size and enjoy!
Store the bars in the fridge for up to a week.
These bars are good warm or cold.
Oat flour is super easy to make at home. Just take rolled oat and blend to a fine flour. Pass the blended oat flour through a sieve to remove any large pieces.This recipe uses cardamom apple butter.