Preheat the oven to 350 degrees F (175 degrees C). Line a 12-cup muffin tin with paper liners.

Whisk together 1 1/2 cups flour, baking powder, baking soda, and salt in a small bowl.

Cream together sugar and butter until light and fluffy. Beat in eggs 1 at a time, making sure to thoroughly combine after each addition. Mix in lemon zest and vanilla extract. Stir in 1/2 of the flour mixture until just combined. Add in the sour cream and lemon juice, stirring until just combined. Add in the remaining flour mixture and stir to combine.

Place raspberries in a small bowl. Sprinkle with 1 1/2 teaspoons flour and and toss to coat. Gently fold raspberries into the batter. Spoon batter into the prepared muffin cups, filling each 3/4 full.

Bake in the preheated oven until a toothpick inserted into the center comes out clean, 20 to 23 minutes. Cool in the tin for 5 minutes. Transfer to a wire rack and let cool completely, about 20 minutes.

Place raspberries for frosting in a small saucepan and cook over medium heat until they burst and release their juices, 5 to 10 minutes. Pour raspberries into a fine mesh sieve set over a medium bowl and use the back of a wooden spoon to press and extract approximately 1/3 cup juice from the berries. Discard seeds and allow juice to cool completely.

Beat butter in a large bowl with an electric mixer until light and fluffy. Beat in powdered sugar 1 cup at a time until incorporated. Mix in 1/3 cup raspberry juice, lemon juice, lemon zest, and salt; beat until combined. Pour in heavy cream and beat until frosting is light and fluffy, about 2 minutes.

Frost cooled cupcakes and top with additional raspberries, if desired.