Mix dry ingredients, including Bisquick baking mix, white sugar, and ground cinnamon into a big bowl. Mix them with a fork.
Create a small hole in the center of the mixture, then add milk and egg to the hole. Mix them well again until the mixture becomes a thick batter.
In a medium bowl, combine Bisquick baking mix, brown sugar, and cinnamon. Then add the chopped cold butter and use your hand to rub it until you get crumbs.
Preheat the oven to 350°F. Line a baking tray with baking paper, then pour half of the batter into a tray and spread it evenly before sprinkling half of the topping. Then add the remaining batter and topping, respectively. Spread them with a spatula.
Place a baking tray in the oven to bake for 20 to 25 minutes. Let it cool to room temperature before slicing. For serving, sprinkle a bit of powdered sugar and cinnamon on top.