Strawberry Cream Slice (original recipe) Biscuits 450 g flour 150g butter, on room temperature 150 g sugar 1 1/2 egg whites 150 g sour cream with 20% mm 1 1/2 tsp baking soda With a mixer beat foamy butter, sugar, egg whites and sour cream. Add sifted flour with baking soda and knead into smooth dough. Leave for half an…