Wash the kale and remove the leaves from the stems.
Bring a large pot of water to a rolling boil, salt well with a tablespoon of rock salt and boil the cavolo nero for about four minutes. Drain and stop the cooking process by placing the hot kale into a cold ice bath (bowl of cold water with ice cubes).
Drain the kale and gently remove any excess water by squeezing it lightly between your hands. Chop roughly.
Gently heat a skillet with 3 tablespoons of olive oil and add 1-2 garlic cloves, peeled and smashed. Keeping the pan over low heat, infuse the garlic into the oil without burning the garlic for about 1-2 minutes.
Add the cooked cavolo nero into the pan and saute with the olive oil and garlic for a couple of minutes. While the kale is cooking, start to toast your bread (you can either do this on a grill pan, on the grill or in a toaster).
Taste the kale for salt and pepper. If you would like to add a squeeze of lemon, add it now.
Top the toasted bread sliced with the sauteed cavolo nero and add an extra drizzle of olive oil. Serve immediately.