Place the butter and milk in a microwave-safe bowl. Heat in 15-second intervals, stirring between each, until the butter is fully melted and the mixture is warm but not hot (about 90 seconds total).

Stir the mixture to combine, then whisk in the vanilla extract. Set aside briefly so it stays warm but not hot.

In a large bowl, beat the eggs and granulated sugar with a hand mixer on high speed until pale, thick, and fluffy, about 1 to 2 minutes.

With the mixer on low, slowly pour the warm milk-and-butter mixture into the beaten eggs and sugar, mixing only until just combined.

Add the all-purpose flour, baking powder, and salt (sift them together first if you prefer). Using a spatula, gently fold the dry ingredients into the wet ingredients until no visible streaks of flour remain. Do not overmix.

Let the batter rest for at least 10 minutes. While the batter rests, preheat your waffle iron and preheat the oven to 200°F (with a wire rack set over a baking sheet) to keep finished waffles warm and crisp.

Lightly brush or spray the preheated waffle plates with oil or nonstick spray.

Gently fold the mini chocolate chips into the rested batter so they distribute evenly and don’t sink.

Pour about 1/2 to 3/4 cup of batter (depending on your waffle iron’s size) onto the center of the waffle iron. Spread slightly if needed, but avoid overfilling. Close the iron and cook about 3 to 4 minutes, or until the waffle is golden brown and crisp. If the waffle sticks when you lift the lid, close and cook another 30 seconds to 1 minute.

Transfer each finished waffle to the wire rack in the preheated oven to keep warm and crisp. Repeat steps 7–10 with the remaining batter.