If using raw pine nuts or walnuts, toast them in a small dry skillet over medium heat for 3–4 minutes, shaking the pan, until fragrant and lightly golden. Remove from heat and let cool briefly.

In a food processor, combine the basil leaves (packed), cooled toasted nuts, grated Parmesan, Pecorino (if using), peeled garlic clove, lemon juice, kosher salt, and black pepper. Pulse several times to break down the ingredients.

With the food processor running, slowly stream in the 1 cup of extra-virgin olive oil until the mixture becomes a smooth, slightly loose paste. Stop and scrape down the sides with a spatula as needed. Taste and adjust seasoning — add more salt, pepper, or lemon juice if desired.

If the pesto is too thick, thin it with 1–2 teaspoons of additional olive oil or a splash (1–2 tsp) of warm water. Transfer the pesto to a bowl or jar. Cover and refrigerate if not using immediately; it will keep 3–4 days refrigerated with a thin film of olive oil on top to preserve color.

Assembly & Cheese

If using a whole mozzarella ball, slice into 1/4-inch rounds. If using ciliegine, drain well and pat dry with paper towel.

Arrange mozzarella slices or balls on a serving platter. If using tomatoes, arrange tomato slices interleaved with mozzarella (Caprese-style) or place tomatoes alongside.

Spoon 1–2 teaspoons of the prepared pesto over each mozzarella slice or a small dollop atop each mozzarella ball. For a shared platter, drizzle 2–3 tablespoons of pesto over the arranged mozzarella and tomatoes and gently spread with the back of a spoon to coat lightly.

Drizzle the extra-virgin olive oil (1 tsp) over the assembled cheese and tomatoes. Sprinkle the coarse sea salt and freshly ground black pepper evenly over the top.

Garnish with whole fresh basil leaves. Serve immediately with toasted baguette slices or crostini for spreading, or refrigerate up to 1 hour before serving. If refrigerating, allow 10–15 minutes at room temperature before serving for best flavor and texture.