Fill a medium saucepan with water and bring to the boil. Add the chopped carrot and boil until soft and delicate (around 10 minutes).
Using a slotted spoon, remove the carrot from the water and place in the cup of a high speed blender.
Add a generous pinch of salt to the water in the saucepan and bring back to the boil.
Add the remaining mac and cheese ingredients to the blender cup with the carrot and blend until very smooth.
In a separate medium saucepan, add the blended sauce mixture and place over medium heat. Whisking constantly, cook until the mixture is thick and glossy. Remove from the heat and set aside.
In the saucepan of boiling water, cook the pasta until al dente (around 10 minutes). Once cooked, strain the pasta and discard the water.
Add the pasta to the sauce and stir well to coat. Set aside.
Find the mould you'd like to use for the bites – make sure it's freezer safe. Silicone works best. You can also use silicone baking moulds, cupcake tins or even ice cube trays. You want your bites to be around 2cm cubes/oblongs. Any bigger and they may not cook through properly.
Fill your mould with the mac and cheese, wrap and freeze for at least 5 hours.