Place your KitchenAid ice cream bowl in the freezer ahead of time (at least 12 hours).

In a food processor or high speed blender, combine the pistachios and 50g of caster sugar. Blend on high speed until you reach a smooth paste; about 6-8 minutes. Set aside for later.

In a medium bowl, whisk together the egg yolks and 50g of caster sugar until paler in colour, then set aside.

Place a medium saucepan over medium heat and add the remaining 50g of caster sugar with half the thickened cream (240ml), milk and salt. Stir regularly, until it reaches a gentle simmer, then remove from heat.

Gradually pour the heated cream mixture into the egg yolks while whisking continuously. Begin with a few tablespoons and gradually increase the amount until it's all incorporated. The slower you pour, the better, as this gradual process helps temper the eggs, preventing any risk of scrambling.

Return the mixture to the saucepan and stir constantly with a spatula or small whisk over low heat until the custard thickens and coats the back of the spoon; approximately 6-8 minutes. Once thickened, remove from the heat immediately and add the remaining thickened cream (240ml), vanilla extract and pistachio paste, then whisk well to combine.

Pour this mixture into a container and refrigerate for at least 3 hours or overnight.

Pour the chilled mixture into your ice cream bowl and churn for 20-25 minutes. Transfer to an airtight container and place a piece of parchment paper or plastic wrap on top and seal with an air-tight lid. Freeze for at least 3 hours.

Preheat oven to 175°C and line two baking trays with parchment paper.

In the bowl of your KitchenAid stand mixer fitted with the paddle attachment, cream the butter and sugar on medium-high speed until light and fluffy; approximately 4-5 minutes. Add the egg and vanilla and beat again until combined.

In a medium bowl, stir together the flour, bicarbonate soda and salt. Add this to the stand mixer and mix on low speed until just combined. Add the white chocolate chips and mix again until just combined.

Take 2 tablespoons of the mixture and roll into balls. Place on the prepared baking trays, leaving a 5cm gap between them. Bake for 14-15 minutes, or until golden, then cool on a wire rack.

Place the white chocolate and coconut oil in a small saucepan over low heat for 3-5 minutes, or until melted, then set aside.

Take a generous scoop of pistachio ice cream and place on top of one cookie and gently spread to the edges. Place another cookie on top and gently press together to compact.

Dip half the sandwich into the melted white chocolate, and dip in the chopped pistachios. Repeat for the remaining cookies.

Serve immediately, or wrap individually in plastic wrap or parchment paper and store in the freezer for up to 3 months.