Cut the eggplant into fine slices with a thickness of approx. 4mm
Place the eggplant slices on a baking sheet and sprinkle them with coarse salt so that the eggplant liquid is removed. Let stand for 10 to 15 minutes and then press down on the eggplant with kitchen paper to remove any spilled water.
Bake the eggplant at 200°C (400°F) selecting static operation for 25 minutes.
Meanwhile, prepare the tonnata sauce by blending all the ingredients (except the eggplant) with an immersion blender.
Place the eggplant on a plate forming a "flower." Then add the "tonnata" sauce and repeat forming two layers.
Voila! Your "tuna" eggplant is ready to be enjoyed.
Notes
You can safely leave the "tuna" eggplant to rest in the refrigerator overnight or for a few hours before eating it.