Smoked trout mousse is a traditional British starter or appetizer. Smoked trout can be purchased in most major markets.
In the bowl of a food processor, pulse trout for 10-15 seconds
Add butter and pulse an additional 5-10 seconds.
Add cream, horseradish, lemon juice and seasonings and pulse until mousse is blended, but not completely smooth, about 10 to 20 seconds.
Taste and adjust seasonings with additional lemon juice, salt and white pepper as needed.