For the lemon poppy seed loaf:

1. Preheat the oven to 350°F (180°C) and grease the bottom and the sides of a 9×5-inch (23×13 cm) loaf pan with melted butter or vegetable oil. Set aside.
2. Sift flour in a medium size bowl. Add baking powder, salt, and mix well. Set aside.
3. In the bowl of a stand mixer fitted with a whisk or using hand mixer on low-speed setting, cream softened butter (NOT MELTED)* and sugar until pale and fluffy. If you end up with a chunky texture while mixing butter and sugar, stop everything, then use a rubber spatula, and press butter and sugar until creamy. You need to have this creamy softened butter-sugar texture before going further in the recipe.
4. Slowly add the beaten eggs to the mixer, one at a time. Add the lemon juice, zest and poppy seeds. Keep the mixer running on low speed and pour in half the milk with half of the flour mixture. Beat until all ingredients are combined, then slowly add the remaining milk and flour, and beat until combined.
5. Transfer the batter to the prepared loaf pan and bake for 50-55 minutes or until a toothpick inserted in the center comes out clean (remember that every oven is different and baking times may vary a little). Remove from the oven and let cool for about 10 minutes in the pan, then transfer to a cooling rack and cool completely.
6. When the cake is cooled, make the icing. Start with adding 1 Tablespoon lemon juice to the powdered sugar then add milk, adjusting quantity if needed. The icing should be thick and not too runny. Spoon icing over he cake and let harden before serving.