Preheat the oven to 350F. Grease and line an 8x8-inch baking pan with parchment. I like to make it so I make a sling with the parchment so I can lift the cake out.

In a large bowl, whisk together the eggs, sugar, vanilla, and coconut extract. Pour in the oil and milk and mix once more. Add in the flour, baking powder, and salt. Mix until combined. Pour the batter into the prepared baking pan and smooth it out into one even layer. The batter should be on the thinner side.

Transfer to the oven to bake for about 26-30 minutes, until a skewer inserted into the center comes out clean and the top is a medium golden brown. Allow to cool in the pan for about 1 hour.

Meanwhile, make the filling. In a saucepan set over medium heat, pour in the sweetened condensed milk, heavy cream, kosher salt, and vanilla. When it’s warm, add a few tablespoons of the milk mixture to a small bowl. Whisk in the corn starch to make a “slurry”. Pour it back into the pan and whisk. Heat it until bubbly and thickened. It should coat the back of a spoon. Pour it into a glass bowl. Fold in the coconut flakes. Press a piece of plastic wrap onto the surface. Transfer to the fridge to chill. It takes about 1 hour to 2 hours to chill.

Remove the cake from the pan. Slice it horizontally in half. Remove the top and set aside. Transfer the bottom part of the cake back to the pan. Pour the milk all over the bottom piece of cake. Add the filling from the fridge and spread it into an even layer. Add the top of the cake onto the filling. Poke the top with a fork all over. Pour the rest of the milk on top of the cake. Sprinkle the top with coconut flakes. Slice the cake into nine slices.