I feel that many of the proofs in Munkres' Topology are like this; some people might say he takes too much time and goes into too much detail. But his exposition of the proof that all subgroups of free groups are free takes an entire chapter, is well organized, and leaves with the feeling that "I could do that". The same is true for many of his lemma/theorems leading up to the Jordan Curve theorem, as well of his proof of Urysohn's lemma and the Tychonoff theorem.