Step 1

Heat oven to 300 degrees and thoroughly grease a 9x5 inch loaf pan. Set aside.

Step 2

In a medium bowl, mix together the flour, baking powder and salt. Set aside.

Step 3

Using a handheld mixer or stand mixer, beat together the melted butter and sugar until it turns a pale light color, about 3 minutes. Slowly add the eggs to the mixture with the mixer on low speed. Add the lemon juice, zest, sour cream and poppy seeds and mix until combined, about 1 minute.

Step 4

Keeping the mixer on low, add half the milk and half the flour until combined. Add the remaining milk and the rest of the flour and gently fold using a rubber spatula until just combined.

Step 5

Transfer batter to the loaf pan, it's okay if it doesn't fill all the way. Bake in preheated oven for 1 hour 10 minutes to 1 hour and 20 minutes. Start checking it at 1 hour and 10 minutes to see if the top middle is set. Check for doneness by inserting a toothpick in the center. If it comes out clean it's done. Cool in pan for 20 minutes then transfer to wiring cooling rack.

Step 6

While the bread is cooling in the pan, add the powdered sugar to a bowl with the water and mix well. Pour the icing over the bread while on the wire rack, with a piece of parchment underneath. Allow to cool completely. Store in an airtight container for up to a week or in the freezer for up to three months.