Put water on to boil for the pasta and, when it’s boiling, add a pinch of salt and cook the pasta, setting a timer for two minutes before the packet instructions say it will be ready.
Put a medium-sized, non-stick frying pan on the stove and tumble in the pecans, then toast them over a medium heat. Once you can smell their scent wafting up from the pan, remove them to a cold plate.
Now stir the butter and sugar together in the frying pan until you have a hot, treacly syrup. Carefully pour in the cream, stir and let the caramel mixture bubble up, add the toasted pecans and a pinch of salt, then turn off the heat.
Just before draining the pasta, lower in a cup to remove a little pasta-cooking water, then toss the drained pasta back into the frying pan with the dark and nutty butterscotch sauce, adding a tablespoon or two of the cooking water if needed to help coat the pasta. Stir to combine before dividing between two bowls. Serve with a little double cream in a small jug to pour over as you eat, if wished.