In a small saucepan over medium heat combine the cream, sugar, sifted cocoa powder and a pinch of salt, cook stirring until smooth and uniform 1-2min. Add the chopped 100gr 70% dark chocolate and cook until fully melted. Take off heat, add the Greek yogurt, mix until fully incorporated. Chill in the fridge overnight.
Freeze in your ice cream maker according to the manufacturer's instructions adding 20gr dark chocolate chunks and the chocolate cookie chunks at the last couple of minutes of churning. Store in the freezer for at least 4 hours until set or spoon right away for a soft-serve consistency.