Preheat oven to 180℃.
Line a 12-hole muffin pan with muffin liners and set aside.
In a large jug or small bowl, combine buttermilk, melted butter, vegetable oil, golden syrup, vanilla, and egg, then whisk to combine and set aside (the mixture will look curdled, that's normal).
250 ml buttermilk, 60 g salted butter, 4 tablespoons vegetable oil, 1 tbsp golden syrup, 2 teaspoons vanilla extract, 1 egg
In a large bowl, place self-raising flour, light brown sugar, and caster sugar and whisk to combine.
375 g self-raising flour, 150 g light brown sugar, 50 g caster sugar
Add the buttermilk mixture to the flour mixture, then fold gently until it's almost incorporated with a few streaks of flour remaining - don't overmix!
Add the chopped dates, and fold until incorporated, and the mixture is just combined.
200 g dates
Scoop the batter into the prepared pan, dividing it equally between the prepared muffin cups.
Bake for 20 - 25 minutes, or until a skewer or toothpick inserted into the centre of a muffin comes out clean.
Remove the muffins from the tin and place on a wire rack to cool.