Grilled Summer Vegetable Sandwich

• 4 slices of fresh sourdough
• 1 tbsp butter
• 1 small eggplant cut into wide thin slices
• 1 small zucchini cut into wide thin slices
• 1 red bell pepper cut into wide thin slices
• 1 heirloom tomato sliced
• 1-2 tbsp olive oil
• Kosher salt & pepper
• Balsamic glaze optional

Basil Lemon Aioli:

• 1/4 cup mayonnaise or Greek yogurt
• 1/3 cup fresh basil leaves or one small handful
• 1 clove of garlic
• 1/2 lemon juiced
• Pinch of salt