The iconic Chef Patrick O’Connell has long been the steward of this idyllic restaurant outside Washington, D.C. In a town whose very existence seems tied to his success, dinner here recalls another era. The dining room is a celebration of maximalist décor and stately grandeur.The menu offers an array of signature preparations, such as the vegetable-forward ratatouille from the garden with roasted garlic custard, the contemporary-minded, tomato-cured hamachi in watermelon gazpacho, and the enduring classic of lobster mousse wrapped in Savoy cabbage dressed with caviar beurre blanc. And all throughout, roaming bread and cheese carts are a reminder of a luxury that’s less and less common.