Preheat oven to 320 degrees and toast the walnuts and pine nuts for about 10 minutes, or until they are warm and fragrant.
Place the bread in the milk and let it soak for a couple of minutes.
Squeeze out the excess milk and add the bread to the food processor, along with the walnuts, pine nuts, garlic, salt.
Blend until it forms a paste.
Add milk, Parmiggiano-Reggiano, the ricotta, Greek yogurt, marjoram and olive oil, and pulse until well combined.