Step 1: Preheat your oven to 210°C (th. 7).
Step 2: Blend the raw fish in the bowl of your Thermomix for 20 sec / 0°C / speed 10. Put it aside in a bowl.
Step 3: In the bowl of your robot, pour the eggs, tomato paste, sour cream, and blend for 30 sec / 0°C / speed 10.
Step 4: Add the fish and mix for 10 sec / 0°C / speed 4.
Step 5: Add the diced basil, stir without mixing. Pour the mixture into a cake mold lined with baking paper, then bake for 40 minutes. Wait for complete cooling before unmolding. Serve chilled with a little mayonnaise.