Preheat your oven to 350°F (175°C). Line a muffin tin with paper cases, or grease the tin with a little butter if you prefer.
Cream the butter and sugar together in a large bowl until the mixture is smooth and fluffy. You can use an electric mixer or just a whisk, but mix well!
In another bowl, whisk the eggs and vanilla extract until combined, then add them to the butter mixture. Stir well until smooth.
Sift the flour, baking powder, and salt together in a separate bowl. Gradually add the dry ingredients to the wet ingredients while mixing. Stir until everything is just combined, but be careful not to overmix.
Pour in the milk and mix again until the batter is smooth. It should be a little thick, but not too stiff.
Fold in the chocolate chips gently, making sure they're evenly distributed throughout the batter.
Spoon the batter into the muffin cases, filling each one about ¾ full. This will allow the muffins to rise nicely.
Bake for 20-25 minutes, or until a toothpick inserted into the center of a muffin comes out clean. They should be golden brown on top and spring back when lightly pressed.
Once they’re done, let them cool in the tin for a few minutes, then transfer them to a wire rack to cool completely.