Line a plate with greaseproof paper.
Cook the nuts in a dry frying pan over a medium–low heat until lightly toasted. Drizzle in 3 tablespoons honey and add the salt. Leave the honey to bubble for 1 minute to coat all the nuts. Allow to cook until they are thick and sticky, then pour the mixture onto the lined plate. Spread the nuts out in a thin layer and leave to cool.
Meanwhile, whip the double cream in the bowl of a freestanding mixer until it forms soft peaks.
Blend the orange zest, ricotta and sugar in the bowl of a food processor until glossy and smooth. Spoon in the cooled nut and honey mixture and pulse until there is a variety of textures.
Spoon into the bowl with the whipped cream and fold together. Ripple in the remaining 2 tablespoons honey.
Spoon into a freezer-proof, sealable container and freeze for at least 6 hours. Serve in bowls topped with chopped pistachios (if using).
