Preheat your oven to 350°F (175°C). Grease and flour a 9x5-inch loaf pan or line it with parchment paper.
Zest and juice lemons. You need the zest of just 2 lemons, but you might need 3 lemons to get enough juice, depending on the size of your lemons.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and poppy seeds. Set aside.
In a large bowl, combine the granulated sugar and lemon zest. Rub them together with your fingers until the sugar is fragrant and slightly moist. This is kind of optional, but I think it adds a nice touch!
Add the melted butter to the lemon sugar and whisk until well combined.
Add the eggs, one at a time, whisking well after each addition.
Stir in the Greek yogurt (or sour cream), lemon juice, and vanilla extract until smooth.
Gradually add the dry ingredients to the wet ingredients, stirring until just combined.
Gently fold in the blueberries.
Pour the batter into the prepared loaf pan and smooth the top. Bake for 50-60 minutes, or until a toothpick inserted into the center of the bread comes out clean. If the top starts to brown too quickly, tent it with aluminum foil. Allow bread to cool completely before adding glaze. Carefully turn your bread out of the pan and set on a flat plate to add glaze. If you greased your pan well at the beginning, it should slide out easily. If it resists, you can gently run a butter knife around the edge of your loaf pan to coax it out.