Step 1

Bring a large pot of water to a boil over medium-high. Add spinach; cook, stirring occasionally, until bright green and wilted, about 45 seconds. Transfer to a large bowl of ice water to cool 3 minutes. Drain. Squeeze spinach between paper towels to remove as much moisture as possible.

Step 2

Combine spinach, parsley, chives, and garlic in a food processor. Pulse until finely chopped, about 12 times. Add ricotta, goat cheese, pecorino Romano, lemon juice, salt, and pepper. Process until smooth, about 25 seconds, stopping to scrape down sides of bowl as needed. Add olive oil, and process until incorporated, 5 to 10 seconds. Spinach-ricotta mixture can be chilled in an airtight container for up to 2 days.

Step 3

Spread about 2 tablespoons spinach-ricotta mixture over each baguette slice. Top with prosciutto; garnish with zest.