Make the dressing.

Place the salt and garlic clove on a small cutting board. Use a knife to scrape and mash the garlic and salt together until you have a paste.

Scrape the paste into a medium mason jar.

Add the remaining dressing ingredients and shake until well combined or use an immersion blender to blend. Set aside.

Make the ratatouille.

Place the eggplant, zucchini, and yellow squash in a large colander. 

Generously sprinkle salt over the vegetables and toss to coat.

Allow the vegetables to sit for 30 minutes to draw out the moisture.

After 30 minutes, rinse the vegetables under cold water to remove most of the salt.

Pat the veggies dry with paper towels.

Preheat the oven to 400 degrees.

Line two large baking sheets with aluminum foil.

Assemble the salted vegetables on one baking sheet and brush lightly with the dressing.

Arrange the onions and tomatoes on the other baking sheet and brush them with the dressing.

Bake in the preheated oven until the vegetables are soft and beginning to caramelize 17-40 minutes.

Check the vegetables and remove the vegetables that are done to a plate and cover with foil.

Allow the remaining vegetables to continue to roast until tender and caramelized.

To make the sandwiches.

Warm a large skillet over medium heat.

Butter one side of each slice of bread.

Place 4 slices of bread, butter side down into the skillet.

Cover each slice of bread with a layer of cheese.

Layer the roasted vegetables and roasted peppers on top of the cheese.

Drizzle the dressing between each layer of vegetables.

Top the vegetables with a layer of cheese.

Place the remaining bread slices, butter side up, on top of the cheese.