- Line a 9 inch x 13 inch pan with parchment paper.
 (This is optional. It makes it really easy to lift the bars out of the pan and
                slice them.)
- In a large bowl or stand mixer, beat :
 1 Pound (4 Sticks) Butter, Softened; until smooth and creamy.
- Add :
 3/4 Cup White Sugar;
 1/2 Cup Brown Sugar, Packed;
 2 Teaspoons Vanilla Extract;
 and beat for 1 to 2 minutes, remembering to scrape the bottom and sides of the
                bowl.
- It should be light and creamy.
- Add :
 4 Cups All-Purpose Flour;
 1 1/2 Teaspoons Salt;
 
- Beat until just combined.
- Do not over mix.
- Add about 2/3 of the dough to the prepared pan.
 (Leave the remaining 1/3 of the dough in the bowl; we're not done with it yet)
- Flour your hands lightly and press the dough into the bottom and up the sides
                of the pan.
- The crust should go about a half inch up the sides of the pan.
- Use a glass or a measuring cup to press the edges and bottom.
- Refrigerate the crust for 20 minutes.
- Don't skip this step!
- Cold shortbread going into a hot oven is what makes for amazing, tender
                crusts.
- Preheat your oven to 375 F or 190 C.
- Bake the crust for about 18 minutes, until the the crust is golden brown.
- Set aside.
- Lower the oven temperature to 350 F or 180 C.
- Meanwhile, add :
 1/2 Cup Walnuts or Pecans, Chopped; to the remaining dough in the mixing bowl.
- Add :
 1 Teaspoon Cinnamon;
 1 Teaspoon Nutmeg;
 (The spices are totally up to you; add as little or as much as you like)
- Mix on low speed just until combined.
- Cover the bowl and stick it in the fridge.
- For the apple filling, start by prepping your apples.
- You can use any combination of apple flavors that you like. A variety is
                always best for baking. (Granny Smith, Fuji, Golden Delicious, Pink Lady are all
                good options.)
- Squeeze :
 2 Tablespoons Fresh Lemon Juice; into a large bowl.
- Peel :
 3 Pounds of a Variety of Apples; core, and cut into 1/8 inch slices.
- The thinner you slice them, the better!
- As you slice the apples, toss them into the bowl with the lemon juice and mix
                around to coat them.
- Stir every couple minutes as you are slicing.
- This will stop your apples from getting brown.
- In a large 10 inch or 12 inch skillet, melt :
 4 Tablespoons ( 1/2 Stick ) Butter; over medium heat.
- Add the sliced apples (and any juice in the bowl) :
 1/4 Cup Sugar;
 1 Teaspoon Cinnamon;
 1/2 Teaspoon Nutmeg;
 (Again, the spice level is totally up to you. Some people don't love nutmeg and
                you can just omit it entirely if you want.)
- Simmer the apples over medium heat, stirring often, for about 12 to 15
                minutes. 
- If it looks like they are boiling too hard, lower the heat to medium-low. 
- When the apples are tender and the liquid has mostly evaporated, turn off the
                heat.
- Pour the apples into the baked crust, leaving a half inch border along the
                edge.
- Get the remaining crust dough out of the fridge.
- Use your fingers to pinch medium pieces of dough and drop them over the
                apples.
- Bake at 350 F or 180 C for 25 to 30 minutes, until the top is golden brown.
- Cool and cut into bars.