Pre-heat oven to 375 F.
Place 3 tablespoons sugar in each llanera. Heat the llanera over the stove on low heat. Make sure the sugar is melted and golden. Use tongs to move the llaneras and to make sure that the heat is well-distributed. Once melted, remove from heat and let the caramel to be cool and firm.
Using a medium bowl, mix egg yolk, evaporated milk, and condensed milk. Slowly stir in circular motion until well-blended. Strain egg-milk mixture using a cheesecloth. Transfer the strained mixture to the prepared llaneras. TIP: Do not beat the egg! Thoroughly stir in one circular motion to avoid bubbles. It takes time, but totally worth it!
Cover the llaneras with foil and place the llaneras in a wide, baking dish with 1-inch water. Bake for about 50 minutes to 1 hour. To check: Prick the flan in the middle with toothpick. It should come out clean.
Remove from oven. Let it cool and refrigerate to set.