Begin by lining a loaf tin with parchment paper and preheating the oven to 180 Celsius/ 350 Fahrenheit.
Place a large frying pan on medium heat and add the knob of butter, followed by the onions and celery. Stir fairly regularly to ensure the onions aren't burning or sticking to the pan.
After 5 minutes, add in the garlic, mushrooms, rosemary, sage and paprika and fry for another 5 minutes, still stirring regularly.
Next, add in the grated carrot and stir for 5 minutes more, then pour the contents of your frying pan into a large bowl and leave to cool.
Once the contents of your bowl has cooled, stir in the nuts, parsley, lemon juice and zest, ¾ of the cheddar cheese, a pinch of salt and pepper, the breadcrumbs and finally, the eggs. The ingredients will start to combine when you add the eggs so make sure your ingredients are well mixed.
Spoon the contents of your bowl into the lined tin loaf. Once full, push down on the nut roast using the back of your spoon. It needs to be tightly packed in to ensure that it roasts as one and can be easily sliced without falling apart later.
Add the last sprinkle of the cheddar cheese to the top of the nut roast and if you like, a sprig of rosemary for decoration.
If you are baking the nut roast in the next couple of days, cover with clingfilm and refrigerate. If you are baking today, cover the top of the tin loaf with tin foil and put in the oven. Leave to bake for around 40 minutes, then remove the tin foil and give it another 10 minutes in the oven.
Remove the nut roast from the oven and leave to sit for around 5 minutes. Then, take out of the tin loaf and you're ready to serve!
