You can make the batter for these delicious muffins the night before so why not get them ready on a Friday evening so that you can start your Saturday with these homemade treats?
Pre-heat the oven to 200c/180c fan/Gas Mark 6.
Chop the butter into cubes and put into a large bowl. Add the sugar and use an electric whisk to cream the butter and sugar, until light and fluffy. Beat the eggs in a separate bowl and then gradually add them to the creamed butter and sugar. Don't worry if they split, this happens sometimes and when you add the flour the batter will come together perfectly.
Sieve in the flour to the mix and mix with a spoon until you have a lovely thick batter. Mix in the blueberries. (If you are making the night before, then refrigerated at this point.
Line a muffin tin with 10 cupcake cases. Divide the mixture evenly between the cases. Sprinkle a little extra caster sugar on top of each muffin.
Bake in the oven for 20 minutes, until risen and golden. These are best served immediately but will last for a day or two if kept in an air-tight container.