First make the herb crust. Beat the butter in a bowl until creamy, then beat in the bread crumbs, tarragon leaves, basil leaves, chervil leaves, and shallot. Season with salt and pepper.
Spread out the mixture between two sheets of wax or parchment paper and chill in the refrigerator for at least 1 hour before using.
Toss the eggplants, zucchini, and tomatoes in half the olive oil.
Heat a ridged griddle pan, add the vegetables, and cook over low heat, turning occasionally, until tender but still firm.
Meanwhile, heat the remaining oil in a skillet.
Add the tenderloins and cook over high heat for about 2 minutes on each side, until browned, then lower the heat and cook, turning occasionally, for 7-8 minutes, until cooked through and tender. Preheat the broiler.
Transfer the pork to the pan of vegetables.
Place a strip of herb crust on top of each tenderloin and broil until the crust is lightly browned.
Serve immediately.
If necessary, wrap the handle of the griddle pan in foil before broiling to protect it from damage.
