Line a lipped baking tray with lightly greased baking paper.
Mix together the sugar, corn syrup and water in a heavy-based saucepan and heat over a low heat until the sugar dissolves. Stir occasionally to help it along
Then Increase the heat slightly and cook until the mixture begins to become golden in colour (25 mins for me, and a thermometer reading of 160C),
Quickly mix in the butter, cardamom and saffron liquid before cooking a for another 3-4 mins until it changes to an even butterscotch colour ( my thermometer read 125C).
Transfer the cardamom pistachio butter toffee mixture onto the lined baking tray and use a spatula to smooth it out as thinly. If there is a layer of still liquid butter on top, then just pour it all away.
Sprinkle on the pistachios and half the rose petals and press them gently into the surface of the toffee.
Cool the toffee completely, cut into pieces with a sharp knife or scissors, sprinkle on the rest of the rose petals and serve.
Adapted from Cardamom–pistachio butter fudge, Saraban by Greg and Lucy Malouf.