Mariska Hargitay and her husband adopted a baby girl, Amaya Josephine, a month ago, and they can finally say their family is whole.

“It’s very soothing to the heart,” Hargitay told PEOPLE . “I feel like she really completed our little family of four.”

The parents are lucky, though–Amaya has a personality that any parent would dream of in a baby. “You never know what you’re going to get with the second baby and so I was sort of nervous about it,” chuckled the proud mama, who stars in Law & Order: SVU. “She’s so zen and so peaceful. I can’t quite believe how easy she’s been–her disposition.”

“She’s not fussy, she doesn’t cry much … she’s just very peaceful,” added Hargitay. “I feed her, she sleeps. It’s pure magic. I feel very blessed.”

Ok, ok, stop rubbing it in!

And it must be nice for Hartigay to have a little helper around the house. Her son August, 4½, enjoys assisting Mom with motherly duties and is very excited about the new addition to the family.

“Today I actually took [Amaya] to pick him up from school,” Hargitay said. “He was very excited when he introduced her to all of his classmates. It’s very sweet, he’s very proud of her.”