Place tomato slices on a rimmed baking sheet that's been lined with parchment paper. Drizzle with olive oil and balsamic vinegar, then sprinkle with Italian seasoning, salt, and pepper.
Bake for 20–25 minutes or until softened and beginning to brown.
Tomato Pesto
Combine all ingredients in food processor and process until smooth.
Cut ciabatta bread into 4 equal sections and then cut each section in half lengthwise. Spread tomato pesto onto the bottom of each ciabatta section. Top with roasted tomatoes, fresh tomatoes, basil leaves, and mozzarella.
Brush grill with olive oil. Place panini onto press and heat until cheese has melted, about 8–10 minutes (depending on the brand and type of press you use).
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