3 tblspns dried porcini mushrooms or porcini powder
Coarse sea salt
Freshly ground black pepper
2 tablespoons finely chopped flat-leaf parsley
1 teaspoon finely chopped mint
4 tablespoons freshly grated Grana Padano cheese
3 tablespoons Fresh Basil Pesto
Bring a large pot of salted water to a boil.
Add Lasagne sheet squares to boiling water and cook until squares begin to float, about 2 1/2 minutes.
Using a slotted spoon, transfer squares to ice water; submerge, then transfer to a large plate and pat dry. Repeat with remaining squares.
Heat oven to 225º. Place bread on baking sheet and cook until dry, 18 to 20 minutes. Tear bread into pieces.
Trim mushrooms and cut stems from caps. Separately cut stems and caps into 1/4-inch-thick slices.
Heat oil and garlic in a large pan over medium-high heat until garlic is pale golden, about 2 minutes.
Add mushroom slices in a single layer and cook, stirring once, until oil is absorbed, about 1 minute.
Sprinkle with generous pinch salt and pepper and reduce heat to low.
Add dried porcini to the pan and cook 2 to 3 minutes (the fresh mushrooms will shed juices), then increase heat to high and cook until juices evaporate, 1 to 2 minutes more. Remove pan from heat and stir in parsley and mint.
Pulse bread cubes in a food processor to make coarse crumbs. Add mushroom mixture and 2 tablespoons cheese; pulse just until combined.
Heat oven to 220º C.
In a small bowl, stir together cornstarch and 2 teaspoons cold water.
Put 1 pasta square on a clean work-surface. Pat 3 to 4 tablespoons mushroom mixture over square to cover all but a 1 cm edge at the top. Using your finger, spread about 1/4 teaspoon cornstarch mixture over edge.
Starting from the side closest to you, gently but tightly roll up pasta; press to seal then cut in half crosswise.
Put cylinders upright and tightly together in a baking dish. Repeat with remaining ingredients, keeping cornstarch mixture stirred together as you go.
Sprinkle cylinders with remaining 2 tablespoons cheese and remaining 2 tablespoons pine nuts. Bake until warmed through, 6-7 minutes.