Potato roulade with chard and cheese

INGREDIENTS FOR 4 PEOPLE
600 g boiled potatoes
200 g '00' flour
30 g Parmigiano
1 egg
Salt, pepper
300 g boiled, chopped chard sautéed in butter
100 g cheese (Provola or mild Caciotta; I used Tremosine Formagella)
FINISH
50 g butter
Extra virgin olive oil
Sage
Tomato sauce (optional)
I peel and cook the potatoes conventionally or in the microwave.

I rice them while hot.

I spread out, let cool briefly, then add Parmigiano, salt and pepper.

I beat an egg with a fork, add to potatoes and gradually add flour.

I quickly form an even ball, adding more flour if needed. I dampen parchment, place the dough on it and flatten with a damp hand.

I form a rectangle about 27 x 30 cm.

I spread chard cooked in strips with oil, a little butter and salt until dry.

I coarsely grate the cheese.

I spread it over the chard.

Using the paper, I form a roll.

I seal well and close the ends.

I wrap in parchment, close like a sweet wrapper and secure with kitchen string. Do not tie the middle as I did, because it expands during cooking.

I put it in a large pan, cover with water, add salt, bring to the boil and cook for 20 minutes.

I let cool before unwrapping. I rushed and it was still soft; wait before removing the paper.

I sauté oil, butter and sage in a small pan.

I slice the roll.

I spread melted butter in a baking dish and arrange slices filling-side up.

I sprinkle with Parmigiano and spoon over butter and sage.

I grill until a crust forms.

Serve with tomato sauce if liked.