Clean the kale, eliminate any leaves that are limp or damaged and remove the central ribs. To do this, hold each leaf firmly at the bottom of the stalk with one hand, then, once more at the bottom, grip it with the other hand and, holding tightly, move upwards along the stalk. Wash these leaves under running water, pat them dry and chop them finely. In a heavy-bottomed frying pan, heat 3 spoonfuls of olive oil with the peeled clove of garlic; when it has browned a little remove it, put the kale into the pan and cook for 10-15 minutes, then turn off the heat and leave to cool. When the kale is cold, transfer it into a bowl with the ricotta, egg and grated pecorino, the crumbled bread, some salt and pepper, and the breadcrumbs. Stir everything together well, until you obtain a homogeneous mixture. Take small amounts of the mixture and, using your hands, shape them into balls slightly larger than a walnut. Roll them in breadcrumbs and then arrange them on a baking tray lined with greaseproof paper. Drizzle a little oil over them and cook in a preheated oven, at 180 °C, for roughly 20 minutes.
In the meanwhile prepare the mayonnaise: put the egg yolks, thoroughly “freed” of the whites, in a bowl. Start adding the oil drop by drop, stirring continuously with a whisk; use one hand to pour in the drops (very slowly!) and the other to stir constantly. The eggs will gradually thicken, and the sauce will acquire its final colour and “appearance”. When you have used up all the oil, after incorporating the last drop, continue stirring and add a pinch of salt and a teaspoon of lemon juice. Taste and, if you wish, gradually add more salt and lemon a little at a time. If you like you can also add a pinch of salt.
When the little balls are cooked, take them out of the oven and leave to rest for about 10 minutes. Then arrange them on a dish and serve accompanied by the mayonnaise.
You can also prepare these tasty little balls with spinach, Swiss chard or turnip tops instead of the Tuscan kale.