Preheat oven to 375°F (190°C). Grease and flour a 9-inch round cake pan.
In a large bowl, cream together the softened butter and granulated sugar until light and fluffy.
Beat in the eggs one at a time, then stir in the vanilla extract.
In a separate bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet ingredients, alternating with the milk, beginning and ending with the dry ingredients. Mix until just combined.
Gently fold in the sliced strawberries.
Pour the batter into the prepared cake pan and spread evenly.
In a small bowl, combine the flour, brown sugar, cold butter, and cinnamon for the streusel topping. Use a pastry blender or your fingers to cut the butter into the dry ingredients until crumbly.
Sprinkle the streusel topping evenly over the cake batter.
Bake for 35-40 minutes, or until a wooden skewer inserted into the center comes out clean.
Let the cake cool in the pan for 10 minutes before inverting it onto a wire rack to cool completely.
Notes
Serve warm or at room temperature. Delicious with a dollop of whipped cream or a scoop of vanilla ice cream.