Peel and cut the potatoes into 1 inch pieces.

In a large pot, boil the potato pieces until tender.

Drain the potatoes and mash them thoroughly.

Add the sour cream, sugar, and butter to the mashed potatoes.

Beat the mixture until it is light and fluffy.

Add the salt, pepper, snipped fresh dill, and cooked and well-drained spinach to the potato mixture.

Gently mix all ingredients until well combined.

Preheat the oven to 400°F (200°C).

Grease a baking dish.

Place the potato mixture in the greased baking dish.

Sprinkle the shredded cheddar cheese evenly over the top of the potatoes.

Bake for 30 minutes, or until bubbly and the cheese is melted and lightly browned.

Let it cool slightly before serving.