Folky, direct soul-pop and balladry made Paolo Nutini famous as a teen during the mid-2000s, but it was his adventurousness that quickly separated him from other British singer-songwriters emerging at that time. When second album Sunny Side Up arrived in 2009, he was drawing on ska, Dixieland jazz, country, and doo-wop, before 2014’s Caustic Love played out like an expansive history of soul and R&B. From the start, Last Night in the Bittersweet reveals the Scotsman’s horizons have only broadened during the intervening eight years. “Afterneath” begins the album with feedback, motorik rhythms, and Tarantino samples as Nutini’s spoken-word lyrics herald “a deep dive into an open mind.” From there, the songs circle around New Wave (“Petrified in Love”), epic indie rock (“Shine a Light”), and hymnal, muted electronica (“Stranded Words [Interlude]”). At the heart of it all is Nutini’s voice. Precociously expressive and versatile from day one, it’s aged handsomely, sounding more lived-in than ever. Here, he contemplates regret, anxiety, optimism, and love as it both blossoms and falters. When the record ends on its most unadorned moment, the gentle folk ballad “Writer,” Nutini sings, “I am your writer who bleeds indecision.” It’s that restless, capricious spirit that continues to make him such an absorbing artist.