Line a 20 x 22 cm tin with high sides with baking paper.
Remove the pihitāhio (pistachios) from their shells. Chop the nuts in to chunks.
Chop the rōpere (strawberries) or whatever fruit you are using. I like to keep them chunky but it is up to you!
Break all of the tiakarete miraka (milk chocolate) and 150 g of the tiakarete parauri (dark chocolate) in to pieces and add them in to a large, heatproof bowl. Add 3 tbsp noni (oil) on top.
Break the remaining 100 g of tiakarete parauri (dark chocolate) in to pieces and add them to a small heatproof bowl. Drizzle over 1 tbsp noni (oil).
Add 3 cm of water to the bottom of two pots that fit the bowls of chocolate snug on top. The bowls should not touch the water. Heat the pots over lower heat until they reach a mild simmer. Add the bowls and gently melt the tiakarete (chocolate), stirring occasionally. Once melted, removed from the heat. Add a ¼ cup of the melted tiakarete parauri (dark chocolate, from the small bowl) to coat the base of the prepared tin. Leave the rest aside for the top of the slice. Add half of the chopped māngohe (marshmallow) on top, making sure there is a 1 cm gap in between each one.
Add the pihitāhio (pistachios), rōpere (strawberries) and buckwheat puffs in to the large bowl of the ranunga tiakarete miraka (milk chocolate mixture). Mix it all together.
Pour half of this mixture over the māngohe (marshmallows) and press it in to the gaps. Use a spatula to press the tiakarete (chocolate) down firmly to fill the spaces, shake the tray a bit too.
Sprinkle over ¼ C of the paramu tauraki-tio (freeze-dried plums).
Add the rest of the māngohe (marshmallows) on top, making sure you allow the gaps in between. Add the rest of the ranunga tiakarete miraka (milk chocolate mixture) and press it down firmly again with a spatula, shake the tray and ensure all the chocolate has settled in between the māngohe (marshmallow). Pour over the reserved tiakarete parauri (dark chocolate) and smooth it out. Sprinkle over a ¼ cup of paramu tauraki-tio (freeze-dried plums). Add the ngākau māngohe (marshmallow hearts) and rikoriko hiriwa (silver glitter) if you are using this decoration.
Refrigerate for 1 ½ hours - 2 hours. Cut in to small pieces, I like to get around 40 pieces out of this slice but that is completely up to you!This will keep in a sealed container in the fridge for a week.