Creating a Lemon Blueberry Sheet Cake is simple if you follow these steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan.
2. Mix Dry Ingredients: In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
3. Cream Butter and Sugar: In a large bowl, beat the softened butter and granulated sugar until light and fluffy.
4. Add Eggs: Add the eggs one at a time, mixing well after each addition.
5. Incorporate Yogurt and Flavors: Stir in the yogurt, lemon zest, and vanilla extract until fully combined.
6. Combine Mixtures: Gradually add the dry ingredients to the wet mixture, mixing until just combined.
7. Add Blueberries: Gently fold in the fresh blueberries, being careful not to break them.
8. Pour Batter: Pour the batter into the prepared baking pan and spread it evenly.
9. Bake: Place in the preheated oven and bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.
10. Cool the Cake: Remove from the oven and allow the cake to cool in the pan for 15-20 minutes before transferring it to a wire rack to cool completely.
11. Prepare the Glaze: In a small bowl, whisk together the powdered sugar and lemon juice until smooth. Adjust the consistency with more lemon juice or powdered sugar as needed.
12. Glaze the Cake: Once the cake is completely cool, drizzle the lemon glaze over the top and sprinkle with extra blueberries for garnish.

These simple steps will guide you in creating an incredible Lemon Blueberry Sheet Cake that will surely impress!