In a large mixing bowl, thoroughly whisk together the all-purpose flour, baking powder, baking soda, salt, and granulated sugar. Whisking aerates the flour for an even rise.
In a separate medium bowl, whisk together the melted butter, oil, and eggs until emulsified. Whisk in the sour cream, whole milk, and vanilla extract until completely smooth.
Pour the wet ingredients into the dry ingredients. Use a silicone spatula to gently fold the mixture together until just combined. Do not overmix.
Gently fold in the chocolate chips with just three or four strokes.
Let the batter sit at room temperature for 15 minutes to hydrate the starches for a thicker, taller bake.