Put the yeast, 2 tbsp flour and 1/3 of the sugar in the heated milk. Leave the mixture aside until the yeast activates. Separately, whip the eggs with the remaining sugar and add the lemon zest and essence to them. Turn the oven on to 131°F (55 °C).
Sift the flour with the salt, make a well and pour the yeast and eggs in it. Knead everything to get a sticky dough. Transfer to a buttered counter and begin kneading, while also adding a little of the remaining butter at a time.
Once all of the butter has been absorbed, transfer the dough to a tray and wrap it with a slightly wet towel. Leave it to rise for 40-50 min. in the middle of the oven.
Take it out and knead again. Weave it into a braid or use your imagination to make it into another shape. Then transfer to a buttered form and smear it with the beaten yolk. Cover with nuts and sugar.
Leave it in the oven for half an hour, then bake at 356°F (180 °C) until it gains a golden crust. If you're worried about it burning, cover with foil and finish baking.