Choose round tomatoes with firm flesh. Cut a small lid off the rounded end. Spoon out the interiors carefully to make a shell. Reserve the interior pulp, discarding the seeds and season with salt and pepper. Cook the green peas in boiling salted water for 2 minutes. Drain and refresh with cold water. To make the aioli, purÄe the garlic in a pestle or food processor. Add the egg yolk, salt and pepper and combine well. With the water running, slowly trickle in the olive oil until the mixture becomes thickened like mayonnaise. In a mixing bowl, combine the tuna, peas, tomato pulp, and aioli. Fill the tomatoes with the tuna mixture. Sprinkle each tomato with a pinch of parsley. Cover with the reserved tomato lids. Serve chilled.
