Using the same saucepan you used to cook the macaroni, add the butter and melt over a medium-high heat. Add the flour and mix vigorously with a whisk for a minute or so. Keep whisking as you gradually add in the milk. Turn down the heat slightly if the bottom is beginning to catch or thicken too quickly.
Keep whisking and cooking until a smooth, thickened sauce begins to form. Add in the ground nutmeg, garlic, and cheddar, and continue to whisk until melted and completely combined. Take off the heat and allow it to cool slightly.
In a medium sized bowl, combine the bacon, cooked macaroni, chives, flour, and béchamel sauce. At this stage, you can taste the mix and adjust the seasoning to preference.
Once you’re happy with the taste, gradually fold in the beaten eggs until you have a mixture almost resembling pancake batter [see notes].
Spoon the mixture into the muffin tin, distributing evenly. Top with some freshly grated parmesan before baking for 15-20 minutes or until golden brown. Turn the tray halfway through the cooking time to achieve an even bake.
Remove from the oven and allow to cool for at least 5 minutes before releasing from the tin and serving.
They can be enjoyed warm or cold with other great party appetisers, like arancini.