Set that oven to 350°F (175°C). Grab your bundt pan and grease it with little butter and a little flour.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and the brown sugar. (Yes, sugar goes in the dry mix for this one. Wild, right?)
In a big bowl, beat the butter until it’s fluffy and dreamy (about 2-3 minutes). Add eggs one at a time. Stir in vanilla and lemon zest and take a deep whiff, it smells like sunshine already.
Add the dry mix to the butter mixture in turns with the Greek yogurt. Start with the dry, then yogurt, then dry again. You get it. Don’t overmix, we’re baking cake, not concrete.
Gently fold in your flour-dusted blueberries. We want them floating like little flavor rafts in a sea of lemony batter.
Scoop that batter into your bundt pan and smooth the top with a spatula.
Pop it in the oven for 50-60 minutes. Peek in around 50 with a toothpick, if it comes out clean, it’s ready to roll!
Let it chill in the pan for 10–15 minutes (don’t rush it), then flip it onto a wire rack and let it finish cooling. This part’s great for scrolling or snacking. Or both.
Mix your powdered sugar and water (or lemon juice) until it’s nice and drizzly. Not too runny, not too thick.
Once the cake is completely cooled (seriously, cool cake + warm glaze = melty mess), drizzle that sweet glaze all over the top.