Preheat the oven to 350°F (175°C). Grease a 9x5-inch loaf pan or line it with parchment.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

In a separate bowl, beat the softened butter and sugar until light and slightly fluffy—about 2–3 minutes with a hand mixer.

Add the vanilla extract and the egg to the butter-sugar mixture. Mix until fully incorporated.

Add about one-third of the dry mixture to the wet, then half the Greek yogurt. Repeat: another third of dry, the remaining yogurt, then finish with the last of the dry. Mix just until combined—do not overmix.

Fold in the blueberries gently with a spatula so they don’t break.

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 comes out clean or with a few moist crumbs. If the top browns too quickly, tent with foil for the last 10–15 minutes.

Let the loaf cool in the pan for 10–15 minutes, then transfer to a wire rack to cool completely before slicing.