Preheat the oven to 350 degrees F. Butter the bottom and sides of a 9-by-13-inch baking pan.

In a medium bowl, whisk the flour, baking powder, salt and malted milk powder together.

In the bowl of an electric mixer fitted with the paddle attachment, beat the butter and brown sugar on medium speed until completely combined. Scrape down the bowl, add the eggs and vanilla, and beat until combined.

Add the flour mixture in two batches until just combined. Add the malted milk balls, chocolate chips, and walnuts and beat until just combined about 10 seconds. The mixture will be thick. Turn the mixture out into the prepared pan and use an offset spatula to spread it evenly.

Bake in the center of the oven for 25 to 30 minutes or until a toothpick inserted into the center of the blondie comes out clean.

Transfer to a wire rack and let cool for 20 minutes. These blondies taste delicious served warm. Cut them into squares and serve with ice cream. They also taste great at room temperature. Once thoroughly cooled, cover tightly with plastic wrap and keep at room temperature for up to 3 days.