How in the world did Slughorn prepare the Felix Felicis in time for his class?

manpreet Best Answer 3 years ago

In the summer of 1996, Horace Sluhorn is persuaded into coming out of retirement by Harry Potter and Albus Dumbledore. Around two months later, he greets his students with potions such as Felix Felicis, the Polyjuice Potion, etc.

Felix Felicis takes six months to prepare, as mentioned later in The Half-Blood Prince:

"Blimey, it's seriously complicated," he said, running an eye down the list of ingredients. "And it takes six months... you've got to let it stew..."
_{Harry Potter and the Half-Blood Prince, chapter 24: "Sectumsepra"}

How did Horace Slughorn manage to prepare the potion for his class?