Separate the egg yolks and egg whites. Use 2 bowls and put 4 egg yolk on each bowl.
In a large bowl, combine the cake flour, sugar, baking powder and salt. Mix until well combined.
Using a separate bowl, combine 4 egg yolks, vegetable oil, orange juice and water. Stir then combine the wet and dry ingredients. Mix well until it is well incorporated.
Use another bowl, beat the egg white until frothy. Add the cream of tartar and continue to beat until soft peak form while gradually adding the sugar. Fold ⅓ of the meringue into the flour mixture then immediately fold the remaining meringue until no streaks remain.
Grease the lyanera or aluminum molder. Pour 1 ½ cup of the batter into the molder. Cover with aluminum foil or cheese cloth. You can also put tea towel on the cover of the lid. This will prevent water from dripping into the cake.
Place in a steamer over boiling water and steam for 15-18 minutes or until the toothpick comes out clean when inserted.
To prepare the yema sauce, heat a pan over low heat. Combine 4 egg yolks, evaporated milk, condensed milk, all purpose cream and vanilla. Stir until well combined.
Add the cornstarch and stir until no more lumps. Continue to cook until it thickens and creamy. Turn off the heat and add the butter. Use a strainer to make the sauce smooth.
Remove the cake from the steamer and let it cool for 10 minutes. When cool, run a knife on the side to loosen the cake from the molder. Place the cake on a serving plate or container, gently pour the yema sauce on top and sprinkle grated cheese.