Apple Pie Bars

Preheat the oven to 350°F / 175°C. Grease and line an 8" square baking dish with parchment paper.
In a medium sized saucepan set over medium heat, brown the butter. Stir the butter occasionally until it turns amber in color and develops little brown specks.
Remove the butter from the heat then set it aside for 10 minutes to let it cool down a tad bit.
Pour the butter into a medium sized mixing bowl, then mix in the water and brown sugar.
Add in the flour, salt, and cinnamon, and mix the ingredients together just until no flour streaks remain.
Place ⅔ of the shortbread batter into your lined baking dish and smooth it out into an even layer. Bake for 15-20 minutes, until the edges turn golden brown. In the meantime, make the apple pie filling.

Wash, peel, and slice the apples into ~1/4" thick slices (just make sure that they're pretty thin).
Add the apples to a large mixing bowl, and toss them with the brown sugar, cinnamon, lemon juice, flour, and apple butter. Make sure that each apple slice has been coated, then set aside
Once the shortbread has golden brown edges, remove it from the oven. Spread the apples over the shortbread into an even layer, then crumble the remaining shortbread over the apples. Bake for an additional 35-40 minutes, until the streusel turns golden brown and the apple mixture is bubbling through the streusel.
Wait for the bars to fully cool to room temperature before slicing to avoid a very messy apple bar situation. You can speed up this process by placing them in the fridge, but only after letting them cool for at least 30 minutes at room temperature.
Once the bars have cooled to room temperature, slice them up, serve them with ice cream and a drizzle of salted caramel sauce if desired, and enjoy!