Boil the spaghetti in a saucepan filled with salted water until al dente. Make the sauce as below while it boils. When the spaghetti is ready, drain and toss with olive oil to stop it sticking. Return the spaghetti to the pan, cover and set aside.
Using a medium frying pan for which you have a fitting lid (or suitable sized platheat the olive oil over medium heat. Add the crushed garlic and cook until starting to brown. Add the shredded kale and sautee gently for a minute.
Throw in around 4 tablespoons of water and cover with a lid. Reduce the heat to low and leave the kale to cook for two minutes.
Meanwhile, open the tin of chopped tomatoes and transfer them to a large bowl. Using a potato masher, crush the tomatoes making sure there are no large pieces. Once the kale is cooked, add the tomatoes to the kale pan and bring the heat back up to medium with the lid on. Cook for around 3-4 minutes or until the tomatoes have reduced and are bubbling nicely. Give it a stir and reduce the heat to a low simmer for a further minute or so. Replace the lid. If the tomato sauce thickens too much, loosen it with a spoon full of pasta water.
When the sauce is done, add it to the spaghetti and serve, topped with meatballs.