Heat the oven to 400°F (200°C). Line a 12-cup muffin tin with paper liners or lightly grease the cups.
Measure the flour, then remove 1 tbsp and toss it with the diced strawberries in a small bowl to coat; set aside.
In a large bowl, whisk the remaining flour with the granulated sugar, baking powder, and kosher salt.
In a separate bowl, whisk the egg, whole milk, neutral oil, and vanilla extract until smooth.
Make a well in the dry ingredients and pour in the wet mixture. Fold gently with a spatula just until a few dry streaks remain.
Fold in the flour-coated strawberries until evenly distributed; do not overmix.
Divide the batter evenly among the muffin cups, filling each about 3/4 full.
Bake until the tops are golden and a toothpick inserted in the center comes out clean, 18–22 minutes. Cool in the pan for 5 minutes, then transfer to a rack to cool at least 10 minutes before serving.