Grease and flour the bottom and sides of an 8-1/2"x4-1/4" loaf pan (skip the greasing and flouring if using a silicone pan.
Sift the flour, baking powder and salt into a bowl.
In a large mixing bowl, beat the butter and sugar until light and fluffy. I used a hand mixer but a wire whisk will do. DO NOT overmix: you will know you have overmixed if the butter solids separate from the fat.
Add the egg and yolk and mix until fully incorporated.
Add the flour and milk in batches. Add a third of the flour first, mix; add half of the milk, mix; add the next third of the flour, mix; then the remaining milk and, finally, the rest of the flour. Stir in the lemon juice and zest.
Pour the batter into the prepared pan.
Make the streusel mixture. Using your fingertips, rub together all the streusel ingredients until the mixture resembles coarse crumbs.
Scatter the frozen blueberries on top of the cake batter. Fill the gaps with the streusel mixture.
Cool the cake in the pan for about half an hour. You may have to use a knife or spatula to loosen the cake from the pan in case pieces of strawberries and blueberries touch the side of the pan. The caramelization would make them stick to the pan. So, loosen the cake gently in places where it sticks to the pan before releasing the cake.
This blueberry lemon streusel cake is best served warm.
To store, place in a tightly-covered container and keep in the fridge.
Alex's Blueberry Lemon Streusel Cake printed from https://casaveneracion.com/alexs-blueberry-lemon-streusel-cake/ for personal use only. Not for republication nor distribution.