You check if they put their money where their mouth is. Generally, a (well-funded) company that pays its (senior) engineers the same as or more than its executives values engineering. To name two, I've noticed both Google and IBM immediately matching friends' competing offers no questions asked. I know two other engineers whose base, cash salary was over USD 400,000 / year. Cash is very expensive to managers, and enormously expensive to startups (equity less so, but still quite a bit) so it is a reliable signal.
A subtler way might be to check the flavour of engineering projects, and particularly their time horizon. Bringing up Google again, one SDE mentioned using machine learning to automate managing their infrastructure. That's the kind of risky, ambitious, long term project you want to look for.
I personally take mentions of intangible things as negative signals from experience. Something along the lines of if someone is trying to reassure you about something, it means they think it's an issue.
In both cases the work was difficult to do, difficult to share across a team (solve a few hard problems well rather than cycle through hundreds of small JIRA tickets) and highly value adding for the company which is why they were willing to pay.
There are many, many different roles in any large company. You can't please all of the people all of the time. I think the key is recognizing what people the company truly values. In some companies it's the software folks, in others it's sales, and in others it may even be front line support. If you are outside the in group, then it may still be a good company to work for as long as you a) recognize you are but a cog in the machine, and b) can be happy doing your non-glamorous work and going home to your (hopefully happy) life. Just make sure you are a well compensated cog.
Someone who has worked a couple places should be able to infer from that whether they are going to be part of a cost or profit center, and whether that environment is something they want.
How do you tell the difference between a company that does value their engineers from one that doesn't if both companies say the same thing? It is not an easy thing to do for sure, but generic uplifting statements don't solve that problem and don't add to job descriptions.