Grind saffron with a teaspoon of sugar until fine.
Warm milk, cream, and remaining sugar in a saucepan over medium-low heat.
Whisk in the saffron mixture and heat only until sugar dissolves.
Chill and churn
Cool the base completely, then refrigerate for at least 4 hours or overnight.
Churn in an ice cream maker until soft-serve texture.
Add cardamom and nuts in the final minutes of churning.
Set and serve
Transfer to a chilled airtight container.
Press parchment on the surface and freeze 2 to 4 hours for firm scoops.
Rest at room temperature for a few minutes, then scoop and serve.
Notes
For no-churn: whip 2 cups cold cream to soft peaks, fold in thick saffron milk base,
stir in nuts, then freeze 6 to 8 hours.Keep the base very cold before churning for the creamiest texture.Do not reduce sugar too much, as it affects scoop texture and helps prevent iciness.