Preheat your oven to 350°F (175°C) and grease a loaf pan with non-stick cooking spray.
In a large bowl, whisk together the yogurt, oil, sugar, eggs, and lemon juice until well combined and smooth.
Add the flour, baking powder, salt, and lemon zest to the wet ingredients and mix until just incorporated, being careful not to overmix.
Gently fold in the fresh or frozen blueberries until evenly distributed throughout the batter.
Pour the batter into the prepared loaf pan and smooth the top with a spatula.
Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean. If the top starts to brown too quickly, loosely cover it with aluminum foil.
While the cake is baking, prepare the icing by whisking together the powdered sugar, lemon juice, and heavy cream (or half-and-half) until a thick, pourable glaze forms.
Once the cake is done, remove it from the oven and let it cool completely on a wire rack.
Once cooled, remove the cake from the pan and drizzle the lemon glaze over the top, allowing it to drip down the sides.
Slice and serve this lemon blueberry loaf cake at room temperature or slightly chilled for a refreshing treat.