Slice eggplants lengthwise about 1/2 inch thick. Heat 2 teaspoons of oil in a large skillet over medium heat. Add single layer of eggplant to skillet and cook until softened, 3 to 4 minutes per side.
Remove from skillet and drain on paper towels. Repeat with remaining eggplant slices adding oil as necessary.
Core tomatoes. Cut into quarters through stem end. Scrape out seeds and veins.
Flatten each piece by pressing gently with flat side of knife. Sprinkle gelatin over water in small bowl.
Heat tomato juice in a saucepan. Stir in gelatin and tomato paste and stir to dissolve. Season with salt and pepper. Remove from heat.
Line a 3 by 7 inch terrine or loaf pan with wax paper, leaving 3-inch overhang. Line the bottom and sides of prepared terrine with slightly overlapping eggplant slices, leaving 2-inch overhang. Dip tomato pieces in tomato-gelatin juice.
Cover eggplant with single layer of tomato. Cover with single layer of eggplant. Continue layering tomatoes and eggplant, ending with eggplant. Fold in eggplant overhang. Fold in wax paper overhang.
Top with weight. Refrigerate at least 2 hours. Just before serving, unmold terrine on a cutting board.
Cut into 1/2-inch thick slices. Arrange on cold plates.
Serve with herb vinaigrette.
Herb vinaigrette:
Mix ingredients in a blender until smooth.
