Cut in butter using a pastry blender or a fork until small pea sized pieces form.
Remove 3/4 C of the mixture and set aside (to use for crumb topping)
To the rest of the mixture, add in baking powder and salt.
Mix in egg yolks, almond extract and milk using a mixer and beat on low for 3 minutes.
In a large bowl whip the egg whites until stiff peaks form.
Fold egg whites into the batter.
Spread batter into a creased and flour springform pan or 9 x 13 pan.
Sprinkle berries over the top of batter. Fold into batter if desired (I leave mine on top)
Add 1/2 tsp cinnamon into remaining crumb mixture.
Sprinkle mixture over top of blueberries.
Bake for 40-50 minutes. If using a springform pan it will take approx., 10-15 minutes longer. Bake until set and the top of cake springs back when lightly touched.