Prepare muffin tray and set aside.
Turn on the oven to 180C / 360F / Gas mark 4.
Whisk the 2 eggs until fluffy and foamy, for about 3 minutes.
Whisk in the 125ml (½ cup) vegetable oil to combine.
Whisk in the 250ml (1 cup) milk to combine.
Whisk in the 200g (1 cup) sugar and 1 tsp vanilla extract to combine.
Mix the 360g (3 cups) flour, 1 tsp baking powder, and ½ tsp salt briefly, then sift it.
Gently mix the flour mixture into the wet ingredients just until combined, do not overmix.
If using, gently mix in the 100g (⅔ cup) raisins or chocolate chips with a spatula.
Divide the batter evenly between 12 muffin tins.
Bake in the preheated oven at 180C / 360F / Gas mark 4 for 20-25 minutes, or until a toothpick comes out clean.
Cool the muffins in the tray for 10 minutes, then transfer to a cooling rack to cool completely.
