This may not be for traditionalists, but I think this way of cooking pasta is clever—the starch from the pasta water comes together to make a velvety, creamy sauce that you wouldn't get if they were cooked separately. I'm not suggesting all pasta be cooked this way, but when a quick dinner is needed this is where I look.
You can swap in any pasta that cooks in about 8 minutes. I've gone for a whole-wheat rigatoni here, but I've had success with quinoa and corn pasta, too. I use delicata squash, but you could use butternut squash instead—the skin is tougher, so it's best to peel it.
Halve the squash and scoop out the seeds, then thinly slice the squash halves into half moons about 2 inches (5 cm) thick. Strip the kale leaves from their stalks and roughly tear any big pieces. Finely slice the stalks, discarding any particularly sinewy ones.
Heat a tablespoon of the olive oil in a large shallow pan over medium heat and add the squash with a generous pinch of flaky sea salt. Cook the squash in the pan for about 10 minutes, stirring every couple of minutes, so that the pieces of squash start to catch and brown at the edges. Fill the kettle with water and put it on to boil.
Once the squash has had its 10 minutes, add the garlic and kale stalks and stir for a minute or so before adding the pasta, lemon zest, lentils, red pepper flakes, stock cube, and 41⁄2 cups (1 liter) of water from the kettle. Cover with a lid and cook over medium heat for 6 minutes.
Next, remove the lid and add the kale leaves and capers. Cover with the lid for a couple more minutes, until the kale is starting to wilt and turn bright green. If your pasta is a little dry, you can add a tiny bit more water, about 1⁄2 cup (100 ml). Remove the lid and simmer for another 2 to 3 minutes, until the water has been absorbed, then take the pan off the heat and stir in the remaining tablespoon of olive oil and half the Parmesan. Taste and add a little more salt if needed, then let sit for a minute or so before piling into bowls and topping with a good grating of the remaining Parmesan.