Preheat oven to 375 degrees F. Line a 12-cup muffin tin with paper liners and set aside. Toss the diced strawberries with 1 tablespoon of flour from the measured amount to help prevent sinking.

In a small bowl, beat together the softened cream cheese, 3 tablespoons sugar, and 1/2 teaspoon vanilla until smooth and creamy. Transfer to a zip-top bag or piping bag and set aside.

In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt until well combined.

In a separate bowl, whisk the melted butter, eggs, milk, and 2 teaspoons vanilla until smooth. Pour into the dry ingredients and fold with a rubber spatula until just combined - a few streaks of flour are okay. Gently fold in the floured strawberries, being careful not to overmix.

Divide batter among the 12 muffin cups, filling each about two-thirds full. Snip a small corner off the cream cheese bag and pipe about 1 tablespoon of filling into the center of each muffin, pushing it slightly below the surface. Top with a few extra strawberry pieces if desired.

Bake for 20-22 minutes, until the tops are golden and a toothpick inserted into the muffin (not the cream cheese center) comes out clean. The cream cheese will still look soft - that's correct.

Let muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely. The cream cheese center will set as they cool.