Boil the plantains in water for 12–15 minutes until they are tender. Then allow them to cool, peel them, and remove the inner strand that holds the seeds, as it can be quite tough.
Mash the cooked plantains with a fork and mix in the all-purpose flour to form a dough. Set this aside while you make the leche poleada.
In a small mixing bowl, dissolve the rice flour in 1/4 cup of milk. Then in a small saucepan, warm the remaining milk with the cinnamon stick, sugar, and vanilla over medium heat. Slowly add the rice flour and milk mixture, whisking constantly until thickened into a custard (about 5 minutes). Remove the cinnamon stick once thickened.
Take a small amount of the plantain dough, flatten it in your hand, and add a spoonful of the leche poleada in the center. Fold the dough over the filling and seal the edges to form an empanada.
Heat the cooking oil in a pan over medium-high heat. Once hot, carefully fry the empanadas in the oil, working in batches to avoid overcrowding the pan.
Fry the empanadas until golden brown on both sides, about 2–4 minutes per side.
Remove them from the oil and drain on paper towels. Immediately coat them with sugar while they’re still warm, then repeat until all the empanadas have been fried and coated in sugar.
Enjoy!