In large bowl, beat butter with sugar until light and fluffy; beat in eggs, 1 at a time, beating well after each addition.
In separate bowl, whisk together flour, poppy seeds, lemon rind, baking powder and salt; stir into butter mixture alternately with milk, making 3 additions of flour mixture and 2 of milk. Spread in greased 8- x 4-inch (1.5 L) loaf pan.
Bake in centre of 325 F oven for 1 hour or until cake tester inserted in centre comes out clean. Place pan on rack.
Lemon Syrup: In saucepan or microwaveable measure, warm sugar and lemon rind and juice until sugar dissolves. With skewer, pierce hot loaf right to bottom in 12 places; pour lemon syrup over loaf.
Let loaf cool in pan for 30 minutes; turn out onto rack and let cool completely. Wrap and let stand for 12 hours before slicing. Makes 1 loaf, 12 slices.
Make-Ahead Tip: Store at room temperature for up to 2 days or overwrap with heavy-duty foil and freeze for up to 1 month.