Preheat the oven to 180°C (350°F) and prepare a baking dish by buttering and flouring it.

Sift together all-purpose flour, whole wheat flour, and baking powder in a small mixing bowl.

In a separate bowl, beat softened butter and brown sugar until light and fluffy using a stand mixer or hand mixer.

Gradually add the egg (or flaxmeal egg replacer), milk, and vanilla extract to the butter-sugar mixture and beat until just combined.

Gradually add the flour mixture and beat until all the flour is well combined to make a smooth cake batter, being careful not to over mix.

Spoon the batter into the prepared baking tin.

Place halved strawberries on top with the cut side down in a single layer.

Sprinkle the remaining brown sugar over the strawberries.

Bake for about 30 minutes, or until the cake is golden brown and a toothpick inserted in the center comes out clean.

Remove from the oven and let the cake rest for 10 minutes before serving.

Serve warm or at room temperature.