Heat the oven to 375°F (190°C). Grease a baking sheet or line it with parchment paper, leaving enough room between portions for the buns to spread slightly.

Combine the flour, baking powder, and salt in a large bowl, then stir in the sugar. This distributes the leavening and seasoning before the butter and liquid are added.

Cut in the butter with a pastry blender or your fingertips until the mixture resembles coarse crumbs. If using softened butter, you may cream it with the sugar first, then add the dry ingredients.

Stir the raisins through the flour mixture before adding the liquid. This helps distribute them evenly and reduces the chance of the raisins sinking toward the bottom.

Beat the egg with the milk in a separate bowl. Pour the liquid into the dry mixture and stir only until a soft, slightly sticky dough forms.

Drop the dough in rounded spoonfuls or use a large cookie scoop to portion 12 to 15 buns onto the prepared baking sheet. Keep the dough rustic and avoid flattening it if you want taller buns.

Bake for 20 to 25 minutes, or until the tops are lightly golden and feel firm. Begin checking near the 20-minute mark because bun size and individual ovens can affect the final baking time.

Let the buns cool briefly on the baking sheet before serving. They are especially delicious while warm, when the buttery crumb is soft and the raisins are pleasantly chewy.