Heat the oven to 180 C / 355 F. Grease a 24-cup mini muffin tin with butter, then dust lightly with flour and tap out the excess.

Zest and juice the lemons. Set aside the measured amounts for the batter and glaze separately.

Whisk together the flour, baking powder, and salt in a medium bowl. Set aside.

In a large bowl, beat the softened butter and sugar together on medium speed for 2 to 3 minutes until pale and fluffy.

Add the eggs one at a time, beating well after each addition. Mix in the vanilla extract and lemon zest.

Add the flour mixture in three additions, alternating with the milk and lemon juice, beginning and ending with flour. Mix until just combined - a few streaks are fine at this stage.

Give the batter a final gentle fold with a spatula to make sure no dry flour remains at the bottom of the bowl.

Spoon the batter into the prepared mini muffin cups, filling each about two-thirds full.

Bake for 11 to 13 minutes, until the tops are lightly golden and a toothpick inserted in the center comes out clean.

Let the cakes cool in the tin for 5 minutes, then transfer to a wire rack and cool completely, about 20 to 25 minutes.

Whisk together the sifted powdered sugar and lemon juice, starting with 2 tablespoons and adding more a teaspoon at a time until the glaze is thick but pourable.

Spoon about half a teaspoon of glaze over each cooled cake and let it drip slightly down the sides.

Allow the glaze to set for 10 to 15 minutes at room temperature before serving or packing.