Preheat oven to 400°F (200°C). Scrub and dry the sweet potatoes, pierce each 6 to 8 times with a fork, rub with the 2 tbsp olive oil, and sprinkle with the 1 tsp kosher salt. Bake directly on the oven rack for 50 to 60 minutes until soft all the way through.

While the potatoes bake, mash together the 4 tbsp softened butter, 2 tbsp brown sugar, 1 tsp cinnamon, 1/4 tsp nutmeg, and 1/4 tsp vanilla extract with a fork until smooth.

Set broiler to high with the rack 6 inches from the element. Cut each baked potato open lengthwise, press the ends to open it up, and spoon 1 tablespoon of cinnamon butter into each one.

Divide the 1 cup mini marshmallows over the 4 potatoes, pressing lightly to keep them in place. Broil for 2 to 3 minutes until golden brown and toasted.

Transfer to plates and drizzle with the optional 1 tbsp honey. Serve immediately.