INSTRUCTIONS TO MAKE THE CAKE:
In a bowl, whisk together dry ingredients.
In a separate bowl, whisk the egg yolks until it is thick and light in color. Beat in the remaining wet ingredients. Add the egg yolk mixture to the flour mixture pouring it into a strainer and whisk until just combined to form the cake batter.
In a bowl of a stand mixer, beat the egg whites until frothy; then add the cream of tartar and slowly stream the sugar and salt. Continue beating until stiff peaks are formed. Fold the egg whites into the cake batter in 3 additions.
Pour the batter into the prepared tube pan and bake in the oven for approximately 1 hour. The cake is done when you can lightly touch the surface and the cake springs back.
Remove the cake from the oven and place on a parchment-lined cooling rack. Using a toothpick, prick multiple holes into the surface of the cake and begin brushing the cake with simple syrup. Allow the cake to sit for a few minutes before inverting the cake onto the parchment to cool completely. Once the cake has completely cooled, loosen the cake and remove the tube pan. Once again, use a toothpick to prick multiple holes into the surface of the cake and brush with more simple syrup. Allow time for the syrup to soak into the cake before decorating
MAKE SYMPLE SYRUP:
Combine sugar and water in a small sauce pan and bring to a boil on the stove. Once it begins to boil, remove from the stove and transfer into a small bowl let cool to room temperature before brushing onto the cake.
TO MAKE YEMA:
In a small bowl, combine egg yolk and evaporated milk and whisk until combined. Strain into a sauce pan. Add condensed milk and whisk until smooth. Add butter and vanilla extract.
Set over medium heat and whisk constantly to prevent clumping. Do not bring to a boil as it will clump. Once the mixture starts to thicken, reduce temperature to low. Whisk constantly to ensure smoothness of yema. It will take about 15 to 20 min of constant whisking to slowly thicken the yema mixture.
Let cool for about 10 min before spreading over baked cake.