1. Soften the cream cheese at room temperature until very pliable.

2. In a food processor or mixing bowl, beat the cream cheese, sour cream, lemon juice, and lemon zest together until completely smooth and fluffy, scraping down the sides as needed.

3. Add the Dijon mustard, chopped dill, chives, smoked paprika, cayenne pepper if using, and chopped capers. Blend or mix again until the herbs and seasonings are evenly distributed.

4. Roughly chop the smoked salmon, then add it to the bowl. Pulse in the food processor for a silky mousse or fold in by hand if you prefer a bit of texture.

5. If the mousse seems too thick, blend in 1 to 2 tablespoons of milk or cream until it is light, airy, and easily spreadable.

6. Taste and season with fine sea salt and black pepper, adding only as much as needed since smoked salmon is naturally salty.

7. Transfer the mousse to a serving bowl or piping bag, cover, and chill for at least 1 hour to allow the flavors to meld and the texture to set.

8. Before serving, swirl the top with a spoon and garnish with extra smoked salmon and fresh dill or chives, then serve with crackers, crostini, or crisp veggies.