Soak tapioca in 1 cup of water for about 30–45 minutes. Drain before cooking.
In a saucepan, combine milk, soaked tapioca, and salt. Cook on low-medium heat, stirring often.
Once pearls turn translucent and soft (about 10–15 mins), add sugar and continue stirring.
If using an egg, beat it separately. Slowly add a few spoonfuls of hot tapioca mix into the egg, then stir the egg mixture back into the pot (prevents curdling).
Simmer for another 5–7 minutes until the pudding thickens. Stir frequently to prevent sticking.
Turn off the heat and mix in vanilla extract. You can also add a pinch of cinnamon or cardamom.
Pour into bowls. Serve warm or chilled. Top with fruits, nuts, or jam if desired.