Preheat oven to 400°F. In a large bowl, combine flour, baking powder, sugar and salt. Use a pastry blender, two forks or your fingers to cut the butter into the flour mixture until it’s coarse and crumbly. In another bowl, beat eggs and milk together. Use a fork to blend wet ingredients into dry until a soft dough forms (you might want to finish bringing it together lightly with floured hands). Gently fold blueberries and walnuts into the dough, distributing them as uniformly as you can.
Drop dough by tablespoon onto a parchment-lined baking sheet. Brush tops lightly with milk. Bake the scones for 10-15 minutes, until the tops are lightly browned. Cool scones on wire racks. Best eaten the same day; freeze in a tightly sealed container or bag to keep them fresh for longer.
Makes about 20 scones.