Preheat oven to 350 F. Spray a springform pan with nonstick cooking spray.

Sprinkle chopped nuts on bottom of pan (if using).

In the bowl of a stand mixer, combine flour, milk powder, baking powder, cornstarch, salt and sugars.

Using the paddle attachment, mix to combine.

In a small bowl, combine oil, eggs, rum and vanilla extract. Mix well.

Add to dry ingredients in the mixer and mix well until thoroughly incorporated.

Transfer the cake batter to prepared baking dish.

Bake for 45 minutes, until a cake tester comes out clean.

Turn off oven and leave cake in oven for 10 minutes.

Meanwhile, in a small saucepan, combine butter, salt, sugar and water.

Cook on medium high heat until the butter melts. Boil for 2 minutes.

Add rum and cook for another 5 minutes on low heat.

Let cake rest for 5 minutes.

With a rubber spatula, go around the perimeter of the cake, making sure it is not sticking anywhere.

Poke holes all over with a toothpick.

Pour rum glaze over cake and wait 2-3 minutes until the cake has absorbed all of the liquid.

Let the cake cool in the cake pan.

Remove the sides of the springform pan.

Flip cake over onto a plate.

Using a rubber spatula, carefully remove the bottom of the cake pan.

Wrap the cake tightly with plastic wrap and then aluminum foil, using 2 plates to invert cake back and forth until it is properly wrapped.

On the next day, unwrap the cake, slice and enjoy!