Chop the mix-ins

• Chop the Oreos into rough pieces.
• Crush the mini eggs.
• Chop the dark chocolate into chunks.

Brown the butter

• Melt the butter in a saucepan over medium heat.
• Cook until the milk solids turn golden and nutty, then cool.

Freeze the Nutella filling

• Scoop the Nutella into small dollops on a tray.
• Freeze until firm.

Make the brown butter dough

• Mix the browned butter with the brown sugar and granulated sugar.
• Beat in the eggs and vanilla.
• Fold in the flour, baking soda and salt by hand until just combined.

Flavor the doughs

• Divide the dough and fold the chopped Oreos into one portion.
• Fold the crushed mini eggs into a second portion.
• Mash the bananas and fold them with the chocolate chunks into a third portion.

Roll and fill the cookies

• Roll the dough into balls.
• Flatten each ball and place a frozen Nutella dollop in the center, then seal the dough around it.

Bake the cookies

• Bake the dough balls at 180 °C until the edges are set and the centers are soft.
• Cool on a rack before packaging.