Preheat the oven to 375°F (190°C) and grease a muffin tin or line with muffin liners.

In a mixing bowl, whisk together the flour, sugar, baking powder, and salt.

In another bowl, combine the milk, vegetable oil, egg, and vanilla extract.

Pour the wet ingredients into the dry ingredients and mix until just combined.

Gently fold in the raspberries.

Spoon the batter into the prepared muffin tin, filling each cup about 2/3 full.

Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center comes out clean.

Allow to cool in the tin for 5 minutes before transferring to a wire rack to cool completely.