While the dough rests, make the filling: bring a large pan of water to the boil and prepare a bowl of iced water. Add the spinach and basil to the pan and blanch for about 30 seconds. Remove from the pan and place straight into the bowl of icy water (this stops it from cooking and will help keep the leaves a beautiful vibrant green colour). Leave to cool for a few minutes in the ice water.
Once cool, squeeze out as much of the liquid as you can then place on a chopping board. Finely chop and tip into a large mixing bowl. Add the ricotta, Parmesan and nutmeg. Mix well then season generously with salt and freshly ground black pepper. Spoon into a piping bag or a sandwich bag that you can snip the corner off.
Lightly dust a couple of large baking sheets and your work surface with semolina flour.
Split your dough in four and roll out each ball of dough into long sheets, I tend to do to the second to last thinness level on my pasta machine.
Place onto your work surface and, using a dough cutter, knife, or ravioli stamp, cut out roughly 7 cm squares. Place the squares onto your prepared trays as you go.
Pipe about a teaspoon of the spinach and ricotta filling onto each square, aiming for just below where you will fold the pasta in half to make triangles.
To shape the triangoli: working one square at a time, lift one corner over the top of the filling to meet the opposite corner, then seal along the edges with your fingers, pressing out any air so the filling is tightly contained. If your dough feels dry at all, you can wet a fingertip and brush the edge to help seal. Set back onto the baking tray. Repeat with the remaining squares of pasta.
Once you have shaped all the pasta, bring a large pan of generously salted water to the boil.