Introduction: Carmel Apple Snickerdoodle Bars (with Texture Variations). These bars bake up quickly and taste fantastic.  They're full of apple and carmel bits, and the top is dusted with cinnamon and sugar.  Baking these makes the whole house smell like the holidays.  I offer three ingredient variations - one for a more cookie like texture, one that's more cake like, and one that is more like biscotti (which is wonderful for dipping in coffee or hot cocoa.)  They are fantastic warm from the oven (especially with a bit of vanilla ice cream), but a bit crumbly.  Once they cool they are much less crumbly, and the soft apple contrasts with the texture of the rest of the bar.
I prefer bars to individual cookies because they take so much less time to make.  This is based on my mom's snickerdoodle cookie recipe, which I've baked over and over making variations each time to get them to be as good or better than her classic cookies! Step 1: Ingredients and Equipment. Ingredients:
- 1 large or two small apples, peeled cored and diced (and tossed in lemon juice if you're moving slowly)
- 1 cups softened margarine OR 1 cup butter flavored Crisco + 6 tablespoons water*
- 1 1/2 cups white sugar or Splenda**
-  2 eggs
-  3 cups flour
-  2 tsp cream of tartar
-  1 tsp baking soda
-  1/2 tsp salt
-  1 cup of carmel bits or cut up carmels
-  2 tbsp white sugar
-  2 tsp cinnamon
*Use margarine if you want a cookie-like texture, use Crisco if you want something more like cake.
**Replacing some or all of the sugar with Splenda will result in a drier, more biscotti-like texture.
Equipment:
-  Standard kitchen gear (bowls, spoons, knives, etc)
-  Parchment/baking paper
-  A baking sheet that's about 11 x 16 or so.
-  A healthy sense of how not to hurt yourself on sharp and hot things while cooking. Step 2: Mix the Dough. Preheat the oven to 375.
Be sure to mix completely before adding the next ingredient!
Mix together the margarine/Crisco and sugar (except for those last 2 tablespoons).
Mix in the eggs.
Mix in the water (if you're using Crisco).
Mix in the flour, cream of tartar, baking soda, and salt all at once.
Without the mixer (if you've been using one), gently stir in the apple and carmel pieces. Step 3: Preparing to Bake. Line the baking pan with parchment paper.  The parchment will give the bottom a nice crispiness and will prevent it from sticking to the pan.
Pour out the dough onto the parchment.  Use your (clean!) hands and/or a rubber scraper to spread the dough across the pan.  It will reach, I promise!  Just keep working it until it reaches, even if it seems impossibly thin.  Make the thickness as even as possible.
Mix together 2 tablespoons of sugar (this is no place for Splenda!) and two teaspoons of cinnamon in a bowl.  Carefully sprinkle this mix over the entire surface as evenly as possible. Step 4: Baking/Doneness Detection. Pop it in the oven and set the timer for 10 minutes.  It will probably take about 15.  
If you've only used sugar (no Splenda) the entire surface will puff up as it bakes.  It will then start collapsing from the outer edge toward the center.  As soon as the puff is out of it it's done.  You can stick a toothpick in it to double check, but it will be perfectly baked.  Don't wait too long, it will dry out faster than it seems (at which point you should tell everyone that they're bars made for dipping in milk or coffee!)
If you've used any Splenda at all the puff and collapse won't reliably happen, so give it 10 minutes, check it with a toothpick in the middle, and pull it when the toothpick comes out clean and it all seems nicely baked and browned around the edges.  It will be fairly dry so the exact baking time isn't as critical. Step 5: Serving. If you didn't read the introduction, these are delicious while they're warm, but they will crumble quite a bit around the edges.  Throw it in a bowl with ice cream and the crumble doesn't matter.  Once they're cool they hold together much better, and they're still delicious.  Box them up airtight and keep them in the fridge if you won't be eating them for a while, the apple bits will go bad more quickly than your standard chocolate chip or something would.