In a heavy bottomed pan/ kadai, dry roast the semolina on medium-low heat, stirring continuously, until dry and fragrant. (about 10 minutes)
Grind the grated coconut with about 1/2 cup water to a coarse paste.
In a mixing bowl, add 5 whole eggs (egg whites+yolks) and only the yolk of the remaining 3 eggs. To this add sugar. Whisk the sugar with egg mixture, until well combined.
Next add melted butter, coconut, nutmeg powder, salt if using, mix well.
Lastly, add the roasted semolina to the above batter, mix well. Cover and let it rest for about 8 hours or overnight. (There is no need to refrigerate this, but if you live in a pretty hot and humid climate, then do refrigerate it).
If you intend to top it with the crust, then knead the dough, roll it out to about 1/8th inch thickness, cut about 1/2 inch strips.
Preheat the oven to 300 degrees F. Line an 8 inch round cake tin or 9-inch square tin with parchment paper and grease with little butter. Add baking powder and mix the batter well before transferring into the prepared cake tin.
Place the strips on the prepared cake batter to create the diagonal pattern. Bake in the middle rack of the oven at 300 degrees F, until it's golden brown, for about 1 hr and 15 mins or until a toothpick inserted in, comes out clean. Baking times will vary depending on the pan size used, keep an eye once the top begins to turn golden brown.
Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.