4 small plum tomatoes, halved
6 oz small buffalo mozzarella balls, torn in half
1/4 cup extra virgin olive oil
2 tbsp balsamic vinegar, plus more for serving
salt and freshly ground black pepper
2 tbsp nonpareil capers, drained and rinsed
2 garlic cloves, thinly sliced
basil leaves, roughly chopped
2 scallions, white and green parts, finely chopped
2 ripe Hass avocados, pitted, skinned, and quartered
Put the tomatoes, red onion, and half of the basil leaves in a bowl. Drizzle generously with olive oil, season well with salt and pepper, and toss gently to blend.
Arrange arugula leaves on serving platter; drizzle with olive oil, balsamic vinegar, season with salt and pepper. Spoon tomato mixture over the top. Scatter with torn mozzarella and remaining basil leaves. Drizzle again with oil and vinegar. Serve.
Place the hot tomatoes, garlic, scallions, and all cooking juices in a bowl. Add the mozzarella, remaining 3 tbsp oil, vinegar, capers, and basil and toss gently.
Place 2 avocado quarters on each of 4 plates. Divide the tomato mixture evenly over the avocados and drizzle with balsamic vinegar. Serve immediately.