Lightly grease llanera or pan with vegetable oil. If using a pan, you may line the bottom with parchment paper for easy removal later.
Combine the dry ingredients in a large bowl. Set aside.
In a separate large bowl, beat egg whites until foamy using a hand or stand mixer using low speed. Gradually add sugar while continuously beating until all sugar is used up. Turn speed to medium and beat until firm peaks form. Set aside.
Add the wet ingredients to the dry ingredients in the bowl with egg yolk added last.
Take ¼ of the meringue and whisk it to the batter to lighten the batter texture. Fold in the rest of the meringue to the batter in 2-3 additions/batches. Fold just until no more white streaks or lumps are visible. Do not overfold or it will deflate the meringue.
Fill ¾ of the llanera or pan with the mixture. Tap them gently to release any trapped air bubbles.
Steam them over low heat for 15-20 minutes or until the inserted toothpick comes out clean. Transfer the llanera/pan into a cooling rack. Once the cakes have cooled down enough to handle, run a knife along the edges of the cake to release it from the mold. Transfer the steamed cakes to individual containers or serving plates.
Make the yema sauce. In a deep skillet or saucepan, combine evaporated milk, condensed milk and egg yolks. Gently mix using a whisk. Bring to a simmer over low heat while gently stirring (with a whisk) regularly to prevent the bottom from burning. Add the all-purpose cream and flour slurry and continue to stir until it starts to thicken (not too thick). Turn off heat then add the butter and mix until well combined.
Ladle and pour yema sauce on top of the cake. Top with grated cheese.