In a small saucepan, combine the apple slices and the whiskey. Set the saucepan over low heat until the whiskey is steamy. Pull the saucepan off the hit, put the lid over it and let the mixture sit til all the whiskey is absorbed. Drop them on a paper towel to remove any excess liquid just before using them.
Meanwhile in a small frying pan, cook the bacon over medium-low until it is deep golden brown and crisp. Transfer the crispy bacon bits with a slotted spoon to a paper towel-lined plate to cool. Save the leftover bacon fat in a jar in the fridge for future use (in a pie crust, cookies, or even Yorkshire pudding).
In the bowl of an electric mixer fitted with a paddle attachment, cream the butter and the two sugars for 3 minutes.
Add the egg, scraping down the sides of the bowl, and beat until it is incorporated, then add the vanilla and mix again.
Sift the dry ingredients into the mixing bowl, then add the oats and mix until just combined.
Drop the whiskey-soaked apple pieces and the bacon bits to the mixer bowl. Beat for just a few seconds more to mix these in.
Cover the bowl and chill the dough over night.
Preheat the oven to 375°F. Prepare two rimmed baking sheets by lining them with parchment.
Scoop the cookies with a large cookie scoop (or a 1/4 cup measure), spacing them a couple inches apart on the cookie sheet, and bake them for about 17 or so minutes, or until the edges are golden brown.
Let cool slightly before transferring the baked cookies to a wire rack to cool completely.
These cookies are best enjoyed the day they are baked but can be stored in a plastic container for several days.