Spray 28 holes of 3 x 12-hole mini muffin pans (1½ tblsp-capacity) with cooking oil.
Layer filo sheets together on a clean bench, brushing in between each layer with melted butter. Cut into 6cm-wide strips, then cut crossways into 6cm squares. Gently press squares into prepared pan holes.
Cook in a moderate oven (180C) for 6 to 7 minutes, or until lightly golden. Stand in pans for 5 minutes before transferring to a wire rack to cool.
Peel and discard skin from trout. Carefully remove flesh from one side and flake into small pieces. Turn over and flake the other side. Discard bones.
Process cream cheese, rind and juice in a food processor until smooth and creamy. Transfer mixture to a piping bag fitted with a plain 1cm nozzle.
Just before serving, arrange pastry shells on a serving platter. Pipe in cream cheese mixture. Top with flaked trout. Sprinkle with chives.
To make summer cocktail, divide nectar evenly (about ¼ cup) among eight chilled champagne glasses. Fill glasses with sparkling wine. Pour a ¼ tsp grenadine gently down the inside edge of each glass (this prevents the drink from clouding).