Spoon 8 tablespoons of softened Nutella onto the baking sheet, flattening them with the spoon and forming discs about 2 inches in diameter.
In a medium bowl, whisk together the flour, baking powder, sugar, and salt.
Pour the wet ingredients into the dry ingredients and mix until just combined. Do not overmix; some lumps are okay. If the mixture is too thick, you can add an extra 1-2 tablespoons of milk to thin it out.
Place a frozen Nutella disc onto the batter and press it down slightly. Then, pour more batter on top to completely enclose the Nutella.