Lucía lived in Manchester with her parents. Her grandmother, Carmen, lived in Seville, in the south of Spain. They spoke on video calls every Sunday.
One Sunday, Lucía had an idea. "Abuela, can you teach me to make your tortilla? I want to cook it for my friends."
Her grandmother was delighted. "Of course! Get some potatoes, an onion, six eggs, olive oil and salt."
Lucía put her phone on the kitchen shelf and started. First, she peeled the potatoes. It took a long time. Then she cut them into thin slices. Her grandmother watched carefully. "Thinner!" she said. "Thinner, like paper!"
Next, Lucía chopped the onion. Her eyes filled with tears. "Abuela, I'm crying," she said.
"Good," said her grandmother. "That means it's a good onion."