In my opinion, the most complex part of Laravel to understand alone is the Eloquent ORM. @JeffreyWay, as always, does a brilliant job digging in the inners of it in his advanced eloquent series [ https://laracasts.com/series/advanced-eloquent ].
Laracasts is a great source of knowledge regarding how to structure and architect an app, not just a Laravel one, but any modern we based app/api. Take a look into the incremental API series, the SOLID principles collection (one of the most comprehensive series about SOLID I've seen), Repository, Service Providers, Testing, Pusher and Mailgun integration and so.
Regarding the framework architecture, besides the above mentioned advanced eloquent series, there are many videos Collections, Relationships, Migrations, Elixir... I could list all of them, and all of them are really helpful to fully understand laravel.
Anyway, I second some of the opinions here, about if you want to learn it start building something ASAP, also the great work @TaylorOtwell has done with Laravel is based on very modern software engineering practices and modern PHP features. So dig into modern PHP best practices and you'll be in the way to fully understand the framework.
Also, as @pmall said, I never saw a framework with a collection of videos about each single feature. If you have an example of it, please share it.
One more thing, take a look at the reading list in laracasts' recommended reading session: [ https://laracasts.com/recommended-reading ]. I did not read all of them, but some of them were very helpful when I started with Laravel. In addition to that list, there is also the excellent book about testing with laravel by @JeffreyWay himself: [ https://leanpub.com/laravel-testing-decoded ].
P.S.: Be kind to who help you without asking nothing in exchange. Serving is a pleasure every time it is recognized with kindness.