As her older brother Jem takes some distance, Scout is feeling a bit lonely and seeks refuge in Calpurnia's kitchen. The "soft side" in Calpurnia comes out, as we see her responding to Scout's need for companionship and attention. If not really approving, she takes less notice of Scout's tomboyish ways than Aunt Alexandra, who later comes on the scene and tries to "reform" Scout.
Scout's relationship with Calpurnia matures, too, when she sees first-hand how Calpurnia lives among her own, maintaining a double standard in the way she speaks to "fit in" on both sides of the tracks. Calpurnia also chastises Scout when she needs it, such as when she made impolite comments when Walter Cunningham comes to lunch and pours syrup all over his plate. Calpurnia remains the Finch family's cook and housekeeper, but she is the closest thing Scout will ever have to a mother...
In chapter 3 we see Calpurnia in a motherly role. She has her own family, but sometimes she becomes the motherly figure in their house. When Scout brings home Walter and makes fun of how he eats, it wasCalpurnia who "requested[her] presence in the kitchen." She scolded her and told her that Walter was her company and he deserves respect from her no matter what. He was their guest. Then "she sent [Scout] through the swinging door to the dining room with a stinging smack."
Then when she came back home from school that day, Cal had missed the kids and made a pan of crackling bread for them. She even gave Scout a kiss as she sent her outside to play while she finished making dinner. Scout was suspicious and said that she must have been "sorry and too stubborn to say so."
Cal plays the role of both the cook and a mother. She corrects Scout when she's wrong, but she also shows affection. Atticus is the parent, but he and Cal both share the same values, so they compliment each other on how they raise the kids.