Adjust oven rack to lower-middle position and preheat to 400°F (200°C). Sift flour into a medium bowl, then whisk in baking powder, sugar, and salt. Add butter and toss to break up the pieces, then smash each one flat between your fingertips. Continue smashing and rubbing until butter disappears into a coarse meal. Add milk chocolate and toss to combine, then stir in milk and cream to form a soft dough.
Turn onto a lightly floured surface and pat into a 7-inch round. Cut into 6 wedges with a chef’s knife, sprinkle generously with toasted or turbinado sugar, and arrange on a parchment-lined half sheet pan. Bake until puffed and golden, about 25 minutes. If you like, serve with clotted cream and strawberry jam, or a spoonful of super-thick and fruity whipped cream .