Makes 30. Champagne gelée adds sparkle to this elegant one-bite appetizer without much effort.

Trout mousse
8 oz. cream cheese, softened
Zest and juice from ½ lemon
8 oz. smoked trout, flaked
1 Tbsp. minced chives
1 Tbsp. chopped mint
Salt, white pepper, and Tabasco

Champagne gelée
1 ¼-oz. package powdered gelatin
1 cup medium-dry Champagne or Cava plus 2 Tbsp.

Assembly and garnish
1 satsuma mandarin orange
Sliced pumpernickel bread, cut into 1½" circles or squares, brushed with oil, seasoned with salt and pepper, and lightly toasted
Pistachios, shelled and toasted

TROUT MOUSSE: Using an electric mixer, beat cream cheese with lemon zest and juice until smooth, about 10 minutes. With a spoon, mix in trout. Add herbs, salt, and pepper to taste and a dash of Tabasco; stir until incorporated.
Do ahead: Up to 5 days in advance.

GELÉE: Mix powdered gelatin with 2 Tbsp. of Champagne and let rest for 5 minutes. Gently heat ½ cup of Champagne (high heat will flatten the effervescence) and, off heat, add to the gelatin. Stir carefully to dissolve. Add remaining ½ cup cold Champagne. Pour through a fine mesh strainer into a small bowl or shallow dish and refrigerate until firm, at least 6 hours.
Do ahead: Up to 3 days in advance.

ASSEMBLY: Peel orange with a knife, eliminating all skin and pith, and remove segments; drain on a paper towel and set aside. Turn out gelée on a cutting board and roughly chop. Using a fork or small spatula, place a scant tablespoon of trout mousse on the pumpernickel round. Garnish the top with an orange segment, gelée, a pistachio, and a chive tip.