Let’s bake these bright and fruity cupcakes:

Make the Cupcakes:

1. Preheat and Prep: Preheat the oven to 350°F (175°C). Line a standard 12-cup cupcake pan(s) with paper liners.
2. Combine Dry Ingredients: In a large bowl, whisk together the 1 1/2 cups flour, baking powder, and salt. Set aside.
3. Cream Butter and Sugar: In a separate large mixing bowl, cream together the softened butter and granulated sugar with an electric mixer on medium-high speed for about 3 minutes, until light and fluffy.  
4. Add Eggs: Add the room temperature eggs one at a time, mixing well until just combined after each addition.
5. Add Flavorings: Mix in the lemon zest (from 2 lemons), 3 Tablespoons of the lemon juice, and the vanilla extract until incorporated. Use a rubber spatula to scrape the sides and bottom of the bowl.
6. Alternate Wet and Dry: With the mixer on low speed, add about one-third of the flour mixture to the wet ingredients, mixing until just combined. Add half of the buttermilk, mixing until just combined. Add another third of the flour mixture, mix. Add the remaining buttermilk, mix. Add the final third of the flour mixture and mix only until just combined. Do not overmix.
7. Prepare and Fold in Blueberries: In a small bowl, gently toss the fresh blueberries with 1 Tablespoon of flour. Gently fold the coated blueberries into the batter using a rubber spatula.
8. Fill Liners: Using a large cookie scoop or spoon, add batter to the cupcake liners until they are about 3/4 full.
9. Bake: Bake for 18-22 minutes, or until a toothpick inserted into the center comes out clean.
10. Cool: Let the cupcakes cool in the pan for a few minutes before transferring them to a wire rack to cool completely.

Make the Lemon Frosting:

1. Cream Butter and Cream Cheese: In a stand mixer fitted with the paddle attachment (or in a large bowl with a hand mixer), cream together the softened butter and room temperature cream cheese until smooth and fluffy.
2. Add Sugar: Gradually add 3-4 cups of powdered sugar, mixing on low speed until incorporated.
3. Add Flavorings: Add 2 tablespoons of lemon juice (from the remaining lemon), the zest from that lemon, the vanilla extract, and a pinch of salt.
4. Beat Until Creamy: Mix on medium-high speed until the frosting is creamy and smooth. If the frosting seems too thick to spread or pipe easily, add a dash of milk or heavy cream (a teaspoon at a time) until it reaches the desired consistency. If it seems too thin, add a couple more tablespoons of powdered sugar.

Assemble:

1. Frost Cupcakes: Once the cupcakes are completely cool, pipe or spread the frosting generously on top of each cupcake.
2. Garnish (Optional): Top the frosted cupcakes with extra fresh blueberries and/or a sprinkle of lemon zest, if desired.

Enjoy these bright and delicious homemade cupcakes!