Melt the butter in a small saucepan over medium heat. Add the flour and whisk until the foaming slows but before the roux starts to darken (5 to 10 minutes). Keep whisking as you pour in the milk. Once the bechemel starts to thicken, add the cheese a little at a time and let it melt. Keep cooking until the sauce coats the back of a spoon. Stir in salt and cracked white pepper to taste. Take the pan off the heat and fish out any unmelted bits of rind and cheese vein.

Cook the bacon in a large pan until crispy. Remove the bacon to drain on a paper towel lined plate and spoon out all but a few tbsp oil from the pan.

Drop the pasta into a large pot of boiling salted water.

Add the garlic and shallot to the pan you used for the bacon. Fry for 2 minutes until fragrant. Stir in the bechamel and turn the heat down to minimum, just to keep it warm.

Once cooked, drag the pasta into the pan of sauce. Add the parsley and toss. The pasta may be very thick, so add pasta cooking water as required to loosen it. Crumble the bacon, and sprinkle it on top of the pasta when serving.