For bun dough, combine yeast, 1 tsp caster sugar and 100ml warm water in a small jug and leave in a warm place until foamy (5-10 minutes). Mix flour, milk powder, remaining sugar and 1 tsp salt on low in an electric mixer fitted with a dough hook, then add yeast mixture, egg and butter and mix to a smooth dough (5-6 minutes). Place in a bowl and prove until doubled in size (30-40 minutes).
For cream cheese filling, beat ingredients in an electric mixer fitted with a paddle until smooth.
To make a crumble topping, combine flour, sugar and butter in a bowl and rub together until mixture resembles coarse breadcrumbs.
Preheat oven to 170°C, and butter twelve 10cm-diameter pie tins. Roll out dough on a lightly floured bench to a 30cm square. Spread three-quarters of the cream cheese mixture over and roll up and away from you to form a log, cut into 12 even pieces and place in tins. Top with remaining cream cheese, berries and a little crumble and bake until golden brown (25 minutes). Serve warm. Breakfast buns are best eaten on the day they’re made.