Preheat the oven to 350°F/175°C. Cut a circle in the top of the pumpkin, like you are cutting a halloween jack-o-lantern. Scoop out the seeds, put the top back on, and bake on a tray in oven for about 45 minutes.
While pumpkin is baking, cook the macaroni according to al dente instructions and set aside.
Fry the bacon in a non-stick pan for a for about 2 minutes. Add the onion and garlic and continue to fry until the bacon is cooked and golden brown. Add it to the al dente macaroni.
In a pot, melt butter. Slowly add the flour while stirring continuously. Cook the flour for at least 1 or 2 minutes. Slowly add the milk, while stirring, until the mixture is smooth. Cook for about 7-8 minutes until the mixture thickens and boils. Add a pinch of nutmeg to the cheese sauce.
Add the grated cheese to the flour mixture and melt it together. Add the cooked macaroni and bacon, onion, and garlic into the cheesy mixture. Add salt and pepper to taste.
Spoon the mac and cheese into the baked pumpkin. Put the pumpkin top back on and bake in the oven for about 30-45 minutes. During the last 10 minutes, remove the top to allow the cheese to crisp up. Allow the pumpkin to rest around 10 minutes before serving.
*cheese mixture to include sharp cheeses like gruyere or sharp cheddar, along with Red Leicester cheese or American Cheddar. A store bought 4 cheese blend would work, as long as one of the cheeses is sharp. If not, add sharp cheddar or gruyere.