This question already has an answer here:
yes, I know, this question is very similar to others I've found.
The above post concludes that if the caster does not choose their own class, they cannot cast the spell learned through the feat Magic Initiate.
My question is this: if the spell learned through Magic Initiate exists in my spell list, but I chose another class for some reason, can I still not cast it using my own spell slots?
For example, let's say I have a wizard and decided to take the Magic Initiate feat, and chose to take the spell from the bard class. The spell of choice: Tasha's Hideous Laughter (or Hideous Laughter).
Since this spell is both on the bard and wizard's spell list, could I use my own spell slots to cast it?