Place the first five ingredients in a large bowl and mix together with a wooden spoon or whisk until smooth.
190 g butter, 250 g caster sugar (superfine sugar), 3 medium eggs, 50 g cocoa powder, 75 g self raising flour
Stir in the chopped chocolate.
75 g milk chocolate
In a separate small bowl, mix the Philadelphia with 3 tsp of caster sugar until soft.
125 g Philadelphia, 3 tsp caster sugar (superfine sugar)
Pour the chocolate mixture into a silicone (or metal) pan in a larger slow cooker, or for a smaller slow cooker e.g. 3.5 litre, pour it into your slow cooker pot lined with baking paper and greased in case any mixture escapes.
Dot the sugared Philadelphia on top and marble it with a knife.
Put the lid on, and cook on high for approx. 1-2 hours until firm round the edges with a wobble left in the middle. Or cook until completely firm if you like your brownies without the gooey-ness.