Halva zarde is a Persian dessert made with saffron, sugar, rose water, and rice flour. It has a unique yellow color and a sweet, floral flavor. It's a popular treat during special occasions in Iran and other Middle Eastern countries.
In a large saucepan, combine the water and sugar. Bring to a boil, stirring until the sugar is dissolved.
Add the saffron threads to the sugar water and let it simmer for a few minutes to infuse the flavor.
Gradually whisk in the rice flour, making sure there are no lumps. Cook the mixture over low heat, stirring constantly until it thickens to a pudding-like consistency. This should take about 15-20 minutes.
Remove the saucepan from the heat and stir in the rose water.
Transfer the Halva zarde to serving bowls or a large dish. Let it cool to room temperature, then refrigerate for at least 2 hours before serving.
Garnish with crushed pistachios or almonds before serving if desired.