I’ve experienced this before. I knocked on their door and had an honest conversation with them. I explained how the smell was filling the entire building and that several other tenants had complained. I asked if they could open a window when cooking and use a fan to blow the smell out. They did it and it helped a lot.

If your neighbor isn’t as kind as mine was, you could always offer to purchase the fan for them. Other option is to get a letter signed by other tenants and present it to your landlord. This shouldn’t done unless you ask the neighbor kindly and they tell you to pound sand.

Good luck!