Rule reminder
In compound tenses, impersonal 'si' always uses 'essere' as the auxiliary (even for verbs that normally take 'avere'). With transitive verbs, the past participle agrees with the object noun. With intransitive verbs, the past participle is masculine singular. With 'essere' + adjective, the adjective is masculine plural: Si è stati fortunati.
Ieri sera ________ benissimo in quel ristorante.