Line a 20 x 20cm baking tin with baking parchment (or use a silicone mould instead, if you like). Warm the milk in a heavy-based pan over a medium heat until steaming, then add the butter and stir until it has melted. Add the sugar, cardamom and saffron, and continue to stir until the sugar has dissolved. Reduce the heat to low and whisk in the milk powder until you have a thick, smooth batter.

Continue to cook the mixture for 10-15 mins, stirring until it starts to clump and come away from the side of the pan, eventually forming a paste-like ball. It’s important to keep stirring to prevent it sticking. Tip the paste into the baking tin and smooth it to the edges using a silicone spatula. Leave to cool to room temperature, about 1 hr, then chill for 30 mins to set.

Break the chocolate into pieces and melt in a heatproof bowl in the microwave in 10-second bursts, stirring between each burst, or over a pan of simmering water, ensuring the bowl doesn’t touch the water. Turn the barfi out onto a chopping board and cut into 25 even squares.

Poke a cocktail stick into one barfi and dip it into the melted chocolate, turning to coat it on all sides. Allow the excess to drip back into the bowl. Repeat with the remaining barfi, transferring them to a sheet of baking parchment, then top with edible rose petals and chopped pistachios. Leave to set completely, about 1 hr. Will keep chilled in an airtight container for two weeks.