Heat the oven to 375° F and grease a 9 x 13 baking pan. Have a Ziploc bag and a hammer, or heavy object (like the bottom of a filled jar), at the ready.
Crush dried penne pasta. It shouldn’t take too long, and it doesn’t need to look any specific way, just needs to be crushed so that it can blend together better in the mixture once you have it on the stove. (I find putting in a Ziplock bag and crushing with a hammer to be easiest.)
Bring 4 cups of water to a boil. Add the pasta once water comes to boil and leave on medium heat to continue to boil. Stir the water to prevent noodles from sticking to the pan. You’ll want the pasta to become very soft and to boil off a lot of the water, about 15 minutes.
Don’t drain the pasta. Adjust stove to medium-low heat. Add the milk while stirring. Continue stirring after milk is added and then add sugar.
In a small mixing bowl, mix cornstarch with 1/4 cup water until well combined. Stir the cornstarch slurry mixture into the pasta on stove. Add 2 tablespoons ghee to the pasta.
Continue to cook over medium-low heat while stirring until the milk has boiled and become very thick, about 5 minutes.
Pour the pasta into the prepared baking pan.
Melt the remaining 2 tablespoons ghee either in microwave or in a small saucepan on stove. Pour melted ghee over your mixture in baking pan.
Bake in oven until the bubbly and the top is beginning to brown, about 30 minutes. The ghee on top will turn golden brown, which is a good indicator of the finished product. The pastry will feel hollow when tapped. A chopstick or knife inserted will come out clean.