Heat oven to 375°F (190°C). Grease a 24-cup mini muffin pan generously. A well-greased pan = fewer “why won't this release?!” moments.

Boil or steam cubes until very tender, 12–15 minutes. Drain thoroughly—excess water = soggy bites.

In a small saucepan, melt 4 tablespoons butter over medium heat, swirling until it smells nutty and turns amber, 3–5 minutes. Don't walk away. Brown to brilliant, not black.

Mash the potatoes. Stir in brown butter, brown sugar, maple syrup, milk/cream, vanilla, cinnamon, nutmeg, and salt. Mix until smooth. Let cool 5 minutes, then beat in the egg. If using boosters (cayenne/orange/bourbon), add now.

In a bowl, combine flour, chopped pecans, 2 tablespoons melted butter, 2 tablespoons brown sugar (borrow from the 1/3 cup if you like it less sweet), and a pinch of salt. Mix until crumbly.

Spoon about 1 heaping tablespoon of sweet potato mash into each mini muffin well. Press lightly to level and create a gentle divot in the center to hold toppings.

Bake 10 minutes to set the mash. This pre-bake ensures the bites hold together when you add toppings.

Remove the pan. Sprinkle each bite with streusel and press 1 or 2 mini marshmallows on top. Don't overpile or they'll slide off like tiny sugar toboggans.

Return to oven for 8–10 minutes, until marshmallows are puffed and golden and streusel is toasty. For deeper color, broil 20–40 seconds—watch like a hawk.

Cool 5–7 minutes. Run a thin offset spatula around edges to loosen. Lift out gently. Sprinkle with a whisper of flaky salt.

Plate warm. Optional drizzle: a few thin lines of warm maple syrup or a swipe of salted caramel for the drama factor.