Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan.

In a large bowl, whisk together the flour, baking powder, and salt.

In another bowl, cream the softened butter and granulated sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition.

Stir in the buttermilk, orange zest, poppy seeds, and vanilla extract until well combined.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Pour the batter into the prepared cake pan and smooth the top. Bake for 40-45 minutes or until a toothpick comes out clean.

While the cake is baking, prepare the glaze by mixing powdered sugar with orange juice until smooth.

Once the cake is done, allow it to cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely before drizzling with the glaze.