
Step 1 · Prep the Vegetables
Slice the eggplant, zucchini, peppers, and red onion. Keep the pieces fairly large so they do not fall through the grill or turn mushy.
Step 2 · Season the Vegetables
In a large bowl, mix 45 g olive oil, 15 g vinegar, 8 g garlic, 6 g salt, 1 g black pepper, and 2 g oregano. Toss the vegetables until well coated.
Step 3 · Heat the Grill
Use medium-high heat. You want visible browning and char, not slow steaming.
Step 4 · Grill the Vegetables
Grill in batches: Eggplant: 3 to 5 minutes per side, Zucchini: 2 to 4 minutes per side, Bell peppers: 4 to 5 minutes per side, Red onion: 3 to 4 minutes per side. The vegetables should be browned, tender, and a little collapsed, but not wet and falling apart.
Step 5 · Make the Spread
Mix 80 g mayo, 15 g Dijon, and 10 g lemon juice or vinegar. This gives the sandwich fat, acid, and a little bite.
Step 6 · Toast the Bread
Split the rolls and toast the cut sides on the grill or in a pan for 1 to 2 minutes. This keeps the sandwich from getting soggy.
Step 7 · Build the Sandwiches
Spread the mayo-Dijon mixture on both sides of the bread. Layer on grilled eggplant, zucchini, peppers, onion, cheese, and greens. Add pesto, roasted red pepper, or tapenade if using.
Step 8 · Grill the Sandwich
Lightly butter or mayo the outside of the bread if you want a crispier finish. Put the assembled sandwich back on the grill pan or skillet. Press it with another pan or a heavy lid. Cook 2 to 4 minutes per side, until the bread is crisp and the cheese melts.
Step 9 · Rest and Cut
Let it sit for 2 minutes before cutting. This helps the cheese and vegetables settle so it doesn’t slide apart.