Begin by making the Simple tomato sauce, heat the olive oil in a saucepan, add the garlic clove and cook until just softened. Add the chopped tomatoes and season. Cook slowly for 25 mins, stirring now and then, until very thick. Do this a day or two ahead of assembling the rotolo, or freeze it for up to 2 months.
Wilt the spinach in a pan over a medium heat, then leave to cool. Squeeze well to remove the excess water, then roughly chop the spinach. Season and leave to cool completely.
Gently fry the garlic in the butter until softened, then remove from the heat and add the marjoram. Tip into a bowl and add the spinach, ricotta and Parmesan.
Roll out the pasta (see step-by-step images). Cut the sheets into 3 or 4 pieces, each roughly 40cm long, and place them on a white tea towel. Using a little water and a pastry brush, stick the sheets together, allowing a 1cm overlap.
Using a spatula, spread the filling over the pasta as evenly as possible, leaving a 1cm border around the edge.
Fold over the edge of the pasta nearest to you and, using the tea towel and the weight of the pasta, roll it away from you like you would a Swiss roll.
Brush the open edge of the pasta with a little water and press together to seal.
Wrap the pasta roll tightly in the tea towel and tie a piece of string round it every 10cm or so (or use a butcher’s knot – see step-by-step images). Tie the ends with string to secure them, leaving a long piece of string at each end to act as a handle.
Bring a large pan of salted water to the boil (a fish kettle is ideal, but a deep roasting tin filled with water works well too) and cook the rotolo for 20 mins. Remove from the water and leave to cool. Heat oven to 190C/170C fan/gas 5.
Gently unwrap the rotolo and cut it into 3cm slices. Arrange the slices in a baking dish. Spoon over the Simple tomato sauce, sprinkle with Parmesan and drizzle with a little olive oil. Bake for 15 mins until the pasta is hot and crisping around the edges.