Blade of Disaster is a new spell from the Icewind Dale: Rime of the Frostmaiden module and is found on pg. 318.
According to the spell description (emphasis mine):
When you cast this spell, you can make up to two melee spell attacks with the blade
The description then goes on to say:
As a bonus action on your turn, you can move the blade up to 30 feet to an unoccupied space you can see and then make up to two melee spell attacks with it again.
It seems that on the round that you cast this spell, you can get up to 4 total attacks. Am I reading this correctly?