Peel the sweet potatoes and grate them on the medium side of a box grater (or use the shredding disk on a food processor). Place the grated potato in a large clean kitchen towel or cheesecloth and squeeze out as much liquid as possible (at least 1–2 tablespoons). Transfer the drained grated potato to a large mixing bowl.

Combine batter

To the bowl with drained sweet potato, add the flour, grated cheddar, sliced green onions, chopped parsley, egg, salt, pepper, and smoked paprika. Stir until a sticky but moldable mixture forms. If it's too wet, add up to 2 tablespoons more flour; if too dry, add 1 tablespoon of water or another beaten egg white.

Shape tots

Dust a work surface and your hands lightly with cornstarch. Scoop about 1 tablespoon of mixture and roll into small cylindrical 'tot' shapes (approximately 1" x 1/2"). Place shaped tots on a parchment-lined tray in a single layer. Repeat until mixture is used, yielding about 24–28 tots.

Heat oil

Pour the vegetable oil into a heavy skillet or Dutch oven to a depth of about 1/2 inch. Heat over medium-high heat until the oil reaches 350°F (175°C) or a small piece of batter sizzles immediately when added.

Fry tots

Working in batches (do not overcrowd the pan), add tots gently to the hot oil and fry 2–3 minutes per side, turning with tongs or a slotted spoon, until golden brown and crisp on all sides. Adjust heat as needed so they cook through without burning (lower to medium if browning too quickly).

Drain and keep warm

Transfer fried tots to a wire rack set over a baking sheet or a plate lined with paper towels to drain. Keep them in a warm oven (200°F / 95°C) if making multiple batches so they remain crisp.

Marshmallow Cream Sauce

Warm cream

In a small saucepan over low heat, warm the heavy cream until it is steaming but not boiling (about 2–3 minutes). Stir constantly to prevent scalding.

Melt marshmallows

Add the mini marshmallows and butter to the warm cream. Stir continuously until the marshmallows are completely melted and the mixture is smooth and glossy, about 2–4 minutes. Keep heat low to avoid scorching.

Finish sauce

Remove the pan from the heat. Stir in the vanilla extract, a pinch of salt, and the optional powdered sugar if you want a thicker or sweeter sauce. Taste and adjust sweetness or salt as desired. If the sauce is too thick, thin with 1–2 teaspoons of warm cream or milk until you reach the desired consistency.

Serve

Transfer the marshmallow cream sauce to a small serving bowl or ramekin and serve warm alongside the sweet tater tots for dipping. The sauce will firm up slightly as it cools — rewarm gently if necessary before serving.