Preheat the oven to 180° C - 356° F and line your 12-cup muffin tin with paper liners or lightly grease them with spray oil.
In a mixing bowl of a stand mixer, cream the softened butter and caster sugar together until you achieve a smooth and fluffy consistency, for about 4 to 5 minutes.
Beat in the eggs, one at a time, ensuring each is fully incorporated before adding the next.
Then, mix in the vanilla bean paste or extract for a delightful aroma.
Stir in the plain natural yogurt and the semi-skimmed or full-fat milk.
In a separate bowl, combine the self-raising flour and salt. Gradually add this dry mixture to the wet ingredients, folding gently until everything is well combined. Be careful not to overmix, as it could result in tough muffins.
Gently fold in the raspberries, ensuring they are evenly distributed throughout the batter.
Using a spoon or an ice cream scoop, fill each muffin cup about two-thirds full with the batter.
Place the muffin tin in the preheated oven and bake for approximately 20-22 minutes or until the muffins turn a golden brown and a toothpick inserted into the center comes out clean.
Let the muffins cool in the tin for a few minutes before transferring them to a wire rack to cool completely.