Even as a teenager, George Frideric Handel’s music was touched by genius. “It is amazing,” said Ulrike Hofbauer, who is singing the lead in “Almira,” Handel’s first opera, written when he was just 19.

Baroque Vocal Fireworks at the Garden Handel composed his three-act opera seria Ariodante in 1735. It was his first opera to be performed at the Covent Garden Theatre, the predecessor of the Royal ...