Berry Streusel Pie

Beat the eggs with sugar until light and fluffy.

Add the vegetable oil, milk, and sour cream or kefir. Mix well.

In a separate bowl, whisk together the flour, baking powder, and a pinch of salt.

Gradually fold the dry ingredients into the wet mixture, gently stirring with a spatula until just combined.

For the streusel, combine the cold butter, sugar, and flour. Rub with your fingertips until crumbly.

Grease a 30 cm baking pan with butter or line it with parchment paper.

Transfer the batter into the pan. Lightly dust the surface with starch.

Top with the strawberries and blueberries. Scatter the streusel evenly over the berries.