Preheat the oven to 375°F (190°C) and grease a 12-cup muffin tin or line with muffin liners.

In a medium bowl, combine melted butter, brown sugar, all-purpose flour, cinnamon, and nutmeg. Mix until crumbly.

In a large bowl, beat together softened butter and granulated sugar until light and creamy, about 1 minute.

Add room-temperature eggs and vanilla extract to the creamed mixture and mix until smoothly incorporated.

In a separate bowl, whisk together all-purpose flour, baking powder, and salt. Gradually add to the wet mixture.

Gently stir in milk, then add the remaining dry ingredients, mixing just until no dry flour is visible.

Fold in finely chopped strawberries with a spatula, being careful not to crush them.

Divide the muffin batter among prepared muffin cups, filling each about three-quarters full.

Sprinkle the prepared crumble topping over each muffin, pressing it lightly.

Bake in the preheated oven for 16 to 18 minutes, until golden brown and a toothpick comes out clean.

Let muffins cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.