[Hi there
you could:

stop cooking and keep windows shut.

Eat out.

starve.

I was going to suggest opening a window, but if that brings smells in from your neighbours then maybe that's not the best solution. Try OUST Or, you could get an extractor fan.

I too live in a flat, I don't get cooking smells though, I just eat out.

I live in a very small flat and the smells of cooking are really hard to get rid of after teatime. Also other people in my building cook curries a lot and those smells can drift in from time to time, not to mention my neighbour's wacky backy. So what's the best solution? Bearing in mind my flat is clean and I use scented candles but they are veery expensive.