Peel and dice the potatoes.

Cook the potatoes in a pot covered with water and a lid for 15 minutes.

Preheat the oven to 350°F (180°C).

In a mixing bowl, mash the tuna with a fork.

Drain the potatoes and add them to the bowl with the tuna and olive oil. Mash together with a fork until smooth.

Add the egg, cornstarch, lemon juice, salt, and pepper. Mix well.

Spoon the mixture into greased muffin tins.

Bake for 15 minutes at 350°F (180°C).