How would you explain this sentence in the context?
The dough had to be thrown away, and even-thing started over. Leandro from heaven, angel of patience, paused to rinse his hands in the wash bucket and dry them on his white trousers. Let me show- you how to do this. Begin with two kilos of the flour. Make a mountain on the counter. Into this mound, with your fingers, crumble the flakes of butter, the salt and soda. Then pull it out like a ring of volcanic mountains around a crater. Pour a lake of cold water in the center. Little by little, pull the mountains into the lake, water and shore together, into a marsh. Gradually. No islands. The paste swells until there are no mountains left, and no lake, only a great blob of lava.
"There. Not just any Mexican can do that, muchacho."
How would you explain the sentence in the second passage: Not just any Mexican can do that? How would you paraphrase “just” in this sentence?
Thanks!