Wash and dry all produce. Preheat the oven to 450 degrees. Cut the eggplant and zucchini into 1/2-inch cubes. Halve the tomatoes. Crush 1 garlic clove with the side of your knife. Strip the thyme leaves of the stems; discard stems.

Roast the veggies: Toss the eggplant, zucchini, tomatoes, crushed garlic, and thyme leaves on a baking sheet (you may need two) with a large drizzle of olive oil and a generous pinch of salt and pepper. Place in the oven for about 20 minutes, tossing halfway through cooking, until soft and golden brown.

Zest, then halve the lemon. Cut one half into wedges. Mince or grate the remaining garlic clove. In a small bowl, combine the mayonnaise, 1/2 teaspoon lemon zest, a squeeze of lemon juice, and as much garlic as you like (start with a little and go up from there). Season with salt and pepper and thin to a drizzling consistency with a teaspoon or so of water.

With 3-5 minutes left to go on the veggies, season the tuna on all sides with salt and pepper. Heat a drizzle of olive oil in a large pan over high heat. Add the tuna to the pan and sear for about 1 minute per side, until golden brown on the outside but very rare on the inside. If you prefer your tuna less rare, simply cook for longer. Remove the tuna from the pan and thinly slice.

Finish and serve: Plate the seared tuna on a bed of thyme-roasted summer veggies, with a dollop of lemon aioli to the side. Serve with a lemon wedge and enjoy!