Step 1: Preheat oven to 350°F (175°C). Line a 12-cup muffin tin with paper liners. Prepare strawberries: puree 1 cup of hulled strawberries until smooth. Finely dice the remaining 1/2 cup of hulled strawberries.
Step 2: In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
Step 3: In a large bowl, using an electric mixer, cream together the softened butter and granulated sugar until light and fluffy, about 2-3 minutes. Scrape down the sides of the bowl as needed.
Step 4: Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Stir in the vanilla extract.
Step 5: With the mixer on low speed, gradually add about one-third of the dry ingredients to the wet ingredients, mixing until just combined. Then, add half of the buttermilk and mix until just incorporated. Repeat with another third of the dry ingredients, the remaining buttermilk, and finally, the last of the dry ingredients. Mix until just barely combined. Do not overmix.
Step 6: Gently fold in the strawberry puree and the finely diced fresh strawberries using a spatula. Mix just until distributed.
Step 7: Divide the batter evenly among the 12 prepared cupcake liners, filling each about two-thirds full.
Step 8: Bake for 18-22 minutes, or until a wooden skewer inserted into the center of a cupcake comes out clean.
Step 9: Remove cupcakes from the oven and let them cool in the muffin tin for 5 minutes before transferring them to a wire rack to cool completely.
Step 10: For the frosting: In a large bowl, beat the softened cream cheese and unsalted butter together with an electric mixer until smooth and creamy, about 2-3 minutes.
Step 11: Gradually add the powdered sugar, one cup at a time, beating until fully incorporated after each addition. Once all the sugar is added, beat on medium-high speed for another 2-3 minutes until the frosting is light and fluffy.
Step 12: Beat in the vanilla extract and a pinch of salt. If the frosting is too thick, add a teaspoon of milk until it reaches your desired consistency. Frost the completely cooled cupcakes.