Smoked Salmon Smørrebrød

INGREDIENTS

• 1/2 mashed potatoes (optional)
• 1/2 sour cream
• 1 finely grated peeled fresh horseradish
• 1 chopped fresh dill
• 1 chopped fresh flat-leaf parsley
• 1 fresh lemon juice
• Kosher salt, ground pepper
• 4 slices Danish rye or pumpernickel bread
• 8 sliced smoked salmon
• 3 radishes, thinly sliced
• 2 salmon or trout roe (optional)
• Dill sprigs and flat-leaf parsley leaves