Preheat your oven to 375° and spray a 9x13 baking dish.
Scrub the sweet potatoes and roast them whole on a foil-lined, rimmed baking sheet for 1 hour or until a fork pierces easily. Remove, carefully cut in half and let cool until safe to handle.
MAKE THE STREUSEL:
In a small bowl, use a pastry blender to cut the whole wheat flour, brown sugar and kosher salt with the cold butter until small, pea-size pieces form.
Add in chopped cooked bacon, pecans and use your hands to form large crumbles. Keep refrigerated until ready to use.
MAKE THE SWEET POTATO CASSEROLE:
In a sauce pan, add 6 tablespoons butter, orange zest, cinnamon and nutmeg. Pour in the bourbon and maple syrup, bring to a low simmer until the butter has melted and small bubbles start to form. Remove off of the heat.
Once sweet potatoes are safe to handle, use a spoon to scrape out the flesh and add it to a large mixing bowl. Season with 1½ teaspoons kosher salt and mash until smooth.
Pour the maple bourbon butter in with the sweet potatoes and mix until incorporated.
Transfer the sweet potato mixture to the prepared baking dish and spread evenly. Scatter with the chilled bacon pecan streusel.
Bake on the middle rack of your preheated oven for 18 to 20 minutes. Let cool 5 minutes before serving.1