Tortelloni Filled with Potatoes and Pancetta

For the dough: Put all the ingredients for the dough in a bowl and knead until smooth. Brush with oil, wrap in plastic wrap and let stand 30 minutes.

For the filling: Peel the potatoes while still hot and press through a potato ricer. Cut the remaining ingredients into very small pieces. Heat the butter in a skillet and saute the pancetta, garlic, sage, thyme and arugula until tender. Transfer to a bowl and stir in the potatoes and the egg. Season with salt, pepper and nutmeg. 

If the mixture is too wet,  stir in the cornstarch.

Divide the dough into 2-3 portions and thinly roll out on a lightly floured surface. With the rim of a glass or a round biscuit cutter, cut out 8 cm (approximately 3 1/4 inches) large circles. Place about 1 tablespoon of filling on the bottom half of each round.

Brush the edges with water, fold the circles in half and press together firmly to seal. Let rest on a floured kitchen towel for 1 hour.

To serve: Meanwhile, wipe the mushrooms with a damp paper towel, cut off the stems and coarsely chop the mushrooms. Rinse the sage and shake dry.

Cook the tortelloni in a large pot of boiling salted water until they bob to the surface, 2-4 minutes.