Preheat the oven to 170°C and line a 2lb cake tin with parchment paper.
In a large bowl, whisk the eggs, sugar and lemon extract until light and fluffy.
Add the cream and oil, combine and whisk in the flour and baking powder.
Add about ¾ of the coated blueberries to the batter and fold in.
Add to the loaf tin and crumble over the streusel topping and remaining ¼ blueberries.
Bake for 45-55 minutes.
To make the streusel topping, rub the butter with the sugar and flour until large crumbs form.
Once cool, whisk the icing sugar with the lemon juice and drizzle over the top of the cake.
Slice, serve and enjoy.
