1. Preheat oven to 375. Line baking sheet with parchment paper.
Combine oats, brown sugar, flour, room temp butter, cinnamon, salt and chopped pecans in bowl of mixer with paddle attachment attached. Mix on low, until crumble is just combined.
Spread onto baking sheet and bake for 8-10 minutes, stirring halfway through. Let cool completely before storing in a air tight container in refrigerator.
Sugar Cookie
Preheat the oven to 350 degrees F. and line cookie sheet with parchment paper or silpat mat.
In stand mixer with flat paddle attachment, beat together sugar and butter for 3-5 minutes. To this, add milk and whipping cream,1/4 cup at a time. Once mixture is smooth, add in the vanilla.
In a separate bowl, mix 2 cups of the flour, baking soda and salt. Stir to combine. Add this to the butter/cream mixture. Once incorporated, start adding flour 1/2 cup at a time, mixing well after each. Add until dough starts pulling away from the bowl.
Using a size 20 cookie scoop, place mounds onto prepared sheet. (I used a 20 scoop and got 22 cookies from the batch.) Bake for 8-10 minutes. DO NOT OVERBAKE. Cookies will be light-colored when done. Let cool on clean dry surface before icing.
Maple Glaze
Combine powdered sugar and 1 Tbsp. milk into a bowl. Add more milk a tablespoon at a time, until mixture becomes smooth. You don't want it to thick or too runny. Add flavored extract.
Putting It All Together
Once crumble and cookies are baked and cool, and icing is made, it's time to assemble!
Take cookie and spread with maple icing, and while icing is still wet, sprinkle with Pecan Oat Crumble. Once icing is set (hardened), store in an airtight container.