Cream the butter and sugar together then slowly add the eggs, mix for three minutes. Add the flour, baking powder, nutmeg, stir to combine, then refrigerate for at least an hour, preferably overnight.
Place a spoonful of muffin mixture into each muffin case, filling each to just over half way. Stud each muffin with about eight blueberries.
Bake in an oven set at 200C/400F/Gas 6 for 20 minutes, or until golden on top. Serve with cream.