Using a combination of rubbing-in method and quick mixing to yield these delicious and soft muffins. Butter gives a nice buttery aroma, while addition of oil yields a lighter texture.
Why rubbed in the butter, instead of melting it as a wet ingredient? When you rub butter into the flour, the fats form a protection layer to the flour protein, delaying the formation of gluten when mixed with the wet ingredients. The result: softer and more tender crumbs that do not stick to your teeth 😉