Prepare all ingredients.
Mix everything for the streusel, grind into crumbs.
For the muffin mix, combine all dry ingredients.
Mix all other ingredients and combine them with dry ones. Mix well.
Beat everything for the filling.
Put the muffin mix into paper muffin cups, make a recess. Put the filling and some berries in it, sprinkle with streusel and put some berries on top.
Bake in the oven at 180 degrees for 25 minutes. Cool down.
Mix everything for the glaze, pour over the muffins.