Alternate adding the milk and the flour mixture to the sugar/butter mixture, ending with flour. Mix until just combined. Using a wooden spoon or rubber spatula, fold in the raspberries very gently.
Pour the batter into the prepared pan (it will be thick). Sprinkle the streusel topping over the batter.
*Nutritional information is an estimate. Please consult a doctor or nutritionist for the most accurate nutritional info.