When creating a rub, a little oil can go a long way toward the even distribution of the ingredients.
To give our Roasted Cornish Game Hens (see related content) shatteringly crispy skin, we rub them with a mixture of two ingredients: kosher salt, which removes moisture, and baking powder, which promotes browning and crisping. Combining the baking powder and salt in a bowl before applying the rub works OK, but it isn’t ideal. That’s because the finer grains of baking powder settle out from the coarser salt, which makes even distribution tricky. To prevent them from separating, we mix the salt with a little oil and then add the baking powder. The oil creates a moist, tacky surface on the salt, giving the baking powder something to cling to, thus ensuring that it distributes evenly and our game hens have evenly crispy skin.