At what point does the author intrude into the story and speak directly to the reader in "The Doll's House" by Katherine Mansfield?

The narrative point of view of Katherine Mansfield’s short story “The Doll’s House” is third person omniscient. This means that the narrator tells the story without including herself in it, that is, without using “I” or “we.”  It is omniscient because the narrator also knows everything there is to know about the story and the characters. However, the narrative of this story is not entirely objective. We get to “hear,” from time to time, the narrator’s own voice throughout the telling of the story, even sensing a degree of connection between the narrator and the character of Else, whom she refers to, affectionately, as “our Else.”

An example of this salient trait of the narrative of “The Doll’s House” is when the narrator seems to move away from the third person objective style, and proceeds to directly involve the reader in the story. This is done as a way to bring the reader inside the situation in order to visualize what the girls are seeing. The part where this is more evident is when the doll's house is described in detail. During this part of the narrative, the narrator uses the pronoun “you.”

The description starts by explaining that the hook that locked the parts of the house together was quite tight. However, it was pried it open, letting the whole front of the dollhouse to swing back.

And –there you were, gazing at one and the same moment into the drawing-room ….

The narrator then continues to describe the house using the perspective of the girls as a way to demonstrate the excitement that the house causes. Here, we see a specific part where the reader may wonder whose perspective is being used: Is it the girls’, or is it the narrator’s own emotions being expressed in this particular instance? Either way, the reader is again engaged, asked to consider a very interesting possibility:

That is-isn't it? -- what you long to know about a house when you put your hand on the knocker. Perhaps it is the way God opens houses at dead of night when He is taking a quiet turn with an angel. . . .

Therefore, in this part of the narrative of the story, the author is actively engaging the reader to visualize the house.  Most of all, the author also wants the reader to experience the sensation of awe and excitement that the dollhouse causes, with its beautiful colors, and its exuberant and unique look.