Preheat oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or lightly grease the pan.

Prepare the cream cheese filling:
In a small bowl, mix softened cream cheese, sugar, egg yolk, and vanilla extract until smooth. Set aside.

Mix dry ingredients:
In a large bowl whisk together flour, sugar, baking powder, baking soda, and salt.

Mix wet ingredients:
In another bowl beat eggs, milk, vegetable oil, and vanilla extract until well combined.

Combine batter:
Add wet ingredients to the dry ingredients and stir gently until just combined. Do not overmix.

Prepare strawberries:
Toss diced strawberries with 1 tablespoon flour to help prevent sinking.

Fold strawberries:
Gently fold the strawberries into the muffin batter.

Make crumb topping:
In a small bowl combine flour and sugar, then stir in melted butter until a crumbly mixture forms.

Assemble muffins:
Fill muffin cups halfway with batter. Add about 1 teaspoon cream cheese filling in the center. Cover with more batter.

Add topping:
Sprinkle crumb topping generously over each muffin.

Bake:
Bake for 18–22 minutes, until muffins are golden brown and a toothpick inserted into the muffin portion comes out clean.

Cool:
Let muffins cool in the pan for 5 minutes before transferring to a wire rack.