In a bowl or measuring cup, whisk together the warm milk and yeast. Set aside for 10 minutes to allow the yeast to bloom.
In a medium bowl, sift together the flour, malted milk powder, baking powder, and salt. Set aside.
In a large bowl, whisk together the melted butter, sugar, and peanut butter. Then add in the egg and vanilla extract. Mix until well combined and smooth.
Carefully pour in the yeast mixture and combine.
Pour in the flour mixture and mix just until combined. Be careful not to overmix the batter. The dough with appear loose and slightly tacky.
Cover the bowl with saran wrap and refrigerate for 8 hours or overnight.
The following morning, preheat your waffle maker to the setting of your choice for 10 minutes.
Brush with a small amount of coconut oil. Then scoop about a 1/4 cup worth of dough and form into a ball. It's okay if the shape is uneven. It will still cook great.
Place the dough in the center of the waffle maker, close, and cook for 3 minutes, or until the waffle is evenly browned and cooked through. Continue cooking each waffle one at a time, making sure to apply more coconut oil if needed, until all the batter has been used. It should make approximately 12 medium waffles.
Store the waffles in the microwave or in a warm oven (200℉) until ready to serve.