Flake the tuna in a mixing bowl.

In another bowl, whisk together the eggs, mustard, sour cream, and chives.

Add the egg mixture to the tuna and mix well.
I don't add salt, as the mustard and tuna provide enough.

Fill cannelé molds three-quarters full with the mixture.

Bake for 30 minutes, then lower the oven temperature to 350°F (180°C).
Let cool in the molds.

Remove from molds.
Now just wait for appetizer time!