Steam the celeriac until tender. Cut the pepper flesh into small diamond shapes. Purée the celeriac with the eggs, butter, cheeses and seasoning. Butter a 1.2-litre/2-pint/5-cup terrine or loaf pan and pour in 2cm/1inch of celeriac purée. Dot some pieces of pepper in it, and cover with carrot purée. Alternate the purées and the pattern of the pepper pieces until the terrine is full. Cover and cook as terrine verte.