In a medium saucepan, melt the lactose free butter and sauté the vegetables for 5 minutes, or until softened. Add the thyme and gently fry for 2 minutes.
Stir in the rice until coated in the fat. Pour in the wine and allow to bubble for a minute or so. Add a ladleful of the stock, bring to the boil, then reduce to a simmer, stirring constantly.
Add another ladleful of stock and stir again until absorbed. Continue adding more stock in this way until the grains of rice are plump and creamy. It should take about 15-18 minutes.
Fold in the crayfish tails for the last few minutes of cooking, followed by the lactose free cream and parmesan. Season to taste with salt and freshly ground black pepper and stir through the parsley. Serve.