Miso Butter Pasta with Fresh Tomatoes

Steps

1. Take the butter out of the fridge right at the start. Bring the 4 l of water to a boil in a large pot with the 20 g of coarse salt, half the usual amount, because the miso will season the sauce.
2. Cut the tomatoes in half crosswise. Grate them, cut side down, on the large holes of a box grater set in a bowl, pressing until only the skin is left in your palm, and discard the skins. You should have about 600 g of pulp.
3. Thinly slice the garlic. Put it in a large skillet with the olive oil over medium-low heat for 2 minutes, until fragrant and barely golden at the edges, without browning.
4. Pour in the tomato pulp, raise the heat to medium-high, and let it reduce at a lively simmer for 10 to 12 minutes, stirring now and then, without salting. The sauce has reduced by half when it is thick, a spoon drawn through it leaves a trail that stays open, and the oil glistens at the edges.
5. While the sauce reduces, drop the pasta into the boiling water and cook it for 2 minutes less than the package time. In a bowl, mash the softened butter with the miso using a fork until you have a smooth beige paste with no white streaks.
6. Toast the nori: hold it with tongs over a gas flame for 3 to 5 seconds per side, or lay it in a very hot dry skillet for 15 seconds per side. It shifts from purplish to deep green, turns brittle, and smells of the sea. Cut it with scissors into 1/8 by 1 1/2 inch (3 mm by 4 cm) strips.
7. Scoop out 250 ml of the pasta water, then drain the pasta or lift it with a spider straight into the skillet, along with 100 ml of that water. Toss for 2 minutes over medium-high heat: the pasta finishes cooking as it absorbs the sauce.
8. Take the skillet off the heat and wait 30 seconds for the bubbling to stop. Add the miso butter in pieces and toss vigorously for 1 minute, adding the remaining pasta water a little at a time, until the sauce is glossy, creamy, and coats every piece. Season generously with pepper and taste: the miso is usually all the salt it needs.
9. Divide the pasta among shallow bowls, tear the basil leaves over the top, and add the nori strips at the very last moment, since they soften within minutes on the sauce. Serve right away.