Preheat your oven to 350°F (175°C). Lightly grease and flour a standard loaf pan or an 8x8 inch baking pan.

In a large mixing bowl, whisk together the sifted flour, baking powder, salt, and sugar. If using, stir in the optional raisins, currants, or nuts.

In a separate, smaller bowl, cream the softened butter until smooth. Gradually beat in the lightly beaten eggs, followed by the milk and vanilla extract. Mix until well combined.

Pour the wet ingredients into the dry ingredients. Stir gently with a wooden spoon or spatula until just combined. Be careful not to overmix; a few lumps are perfectly fine.

Spoon the batter evenly into the prepared baking pan. Smooth the top with the back of a spoon.

Bake for 30-40 minutes, or until a wooden skewer inserted into the center comes out clean. The top should be golden brown.

Let the baked good cool in the pan for 10 minutes before inverting it onto a wire rack to cool completely.