Place eggs in a saucepan and cover completely with water. Bring to a boil over high heat. Once the water has reached a boil, set a timer for 6 minutes. Drain the hot water and run the eggs under cold water until they cool down. Once cooled, tap the eggs all over with the back of a spoon to gently crack the shells, then carefully peel the shells from the eggs.
Slice each egg in half, lengthwise. Gently remove the yolks and place them in a mixing bowl.
Whisk the egg yolks with mustard and mayonnaise. Adjust the seasoning with salt and pepper to taste. (Add more mayonnaise or mustard if necessary to reach the desired flavor and creamy consistency.)
Spoon the egg yolk mixture into the egg white halves. Sprinkle with paprika and top with capers.