Preheat the oven to 400 degrees F (200 degrees C).
Using a fork, poke holes in the Sweet Potato (5) 5-6 times. Rub with Olive Oil (to taste) and season with Salt and Pepper (to taste).
Place on a baking sheet and bake for 50 minutes to 1 hour, or until fork tender and the skin is dark. Allow to cool. This step can be done the night before!
Once cool enough to handle, remove and discard the skin. Transfer the cooled potatoes to a large bowl.
Add the All-Purpose Flour (1/2 cup), Brown Sugar (1/4 cup), Pumpkin Pie Spice (1/2 teaspoon), Butter (2 tablespoon), and Heavy Cream (1/4 cup). Mix until combined.
Increase the oven temperature to broil.
Add the Marshmallow (1 cup) to a baking sheet and roast until charred, about 2 minutes. Keep an eye out, this happens fast!
Once marshmallows are crisp and charred, fold into the sweet potato mix. Add Kosher Salt (1 pinch) and taste for flavor. You do not want this to be super sweet, because we still have the topping!
In a small bowl, whisk the Egg (2) and fold into the sweet potatoes. Transfer to an oven safe dish.
For the topping, combine the All-Purpose Flour (1/2 cup), Brown Sugar (1/4 cup), Pecans (1 cup), Sage Leaves (6), Kosher Salt (1 pinch), and Sunkist Orange (2 teaspoon) in a bowl. Taste for flavor and adjust as needed.
Using your hands, mix in the Butter (5 tablespoon) to evenly distribute. Mix should be crumbly, but will stick if pressed together.
Sprinkle the topping evenly over sweet potatoes.
Reduce the oven to 400 degrees F (200 degrees C) and bake for 35 minutes, or until heated through.