Preheat the oven to 375°F (190°C).
Prepare the filling: In a large bowl, combine the salmon, leeks, cream cheese, dill, lemon juice, salt, and pepper.
Melt the unsalted butter and brush a muffin tin with a thin layer.
Layer the phyllo dough: Place one sheet of phyllo in the muffin tin, brushing with melted butter, and repeat with another sheet at a slight angle.
Spoon the filling into each phyllo cup, about two-thirds full.
Top with additional phyllo layers if desired, brushing each layer with butter.
Bake for 20-25 minutes or until the phyllo is golden brown and crisp.
Allow to cool slightly before carefully removing from the muffin tin.
Serve warm or at room temperature, garnished with extra dill if desired.