icing sugar until the mixture becomes thick and opaque.
Instructions
Preheat the oven to 320 degrees Fahrenheit (fan) or 350 degrees Fahrenheit (no fan) and line a 2.2 pound loaf tin with grease proof paper.
Cream the softened butter and caster sugar together in a stand mixer until pale and fluffy (about 5 minutes). Add the lemon zest halfway through and keep mixing.
Add the two eggs and keep mixing. If the mixture curdles, add some flour and keep mixing.
Mix together the flour, baking powder, almonds, and salt and fold this into the creamed butter mixture (you may need to do this in a few additions). Add the cream and stir through.
Put the blueberries in a bowl and toss them in 1 teaspoon of flour. This will prevent them from sinking while baking.
Put one third of the mixture into the loaf tin. Sprinkle over with half of the berries, and repeat with another layer of batter, berries finished off with a final layer of batter and bake for an hour (check with a toothpick to make sure that it has cooked through).
Once the cake has been cooked, take it out of the oven and let it rest for a few minutes before turning out onto a cooling rack. Poke the top of the cake with small holes all over.
Make a simple sugar syrup with the juice of one lemon and 1.8 oz caster sugar heated on the hob until the sugar dissolves. Pour this over the cake. Leave to rest until cooled.
Once cooled, you can make a mixture of icing sugar and the juice of a lemon and zig-zag this over the top of the cake, but it's completely optional.