Preheat oven to 350 degrees. Lightly spray (or butter and flour) an 8x4-inch loaf pan, set aside.

In the bowl of a stand mixer, beat together the butter, sugar, lemon zest, and vanilla extract until light and fluffy, about 2-3 minutes. Add the eggs one at a time and mix until incorporated.

In a medium size mixing bowl whisk together the flour, poppy seeds, baking powder, baking soda and salt.

In a small mixing bowl combine the sour cream, milk and lemon juice, mix together until smooth.

With mixing speed on low, alternate adding the dry ingredients and the wet ingredients in three separate additions. Mix until a smooth batter forms.

Pour batter into the prepared loaf pan and sprinkle with sliced almonds (if desired). Place into the oven to bake for 45 minutes to 1 hour 10 minutes. You may need to tenting the loaf with foil half way through the baking process to prevent over-browning. The loaf may look slightly moist in the center, especially in the crack, but as long as it's mostly set (not runny) remove it and allow it to cool in the pan for 30 minutes before removing from the pan and transferring to a wire rack and poke holes all over the top of the bread using a cake tester or toothpick.

To prepare the glaze combine ingredients in a small saucepan set over medium heat. When the sugar has completely dissolved, pour over the cooled loaf and allow to drip over the edges and sides. Allow to sit for 20 minutes to harden before serving.