Playing a a mom on the verge of a nervous breakdown while trying to organize her daughter's birthday party in the comedy Motherhood (out Oct. 23) wasn't a difficult scenario for Uma Thurman to relate to. The hands-on 39-year-old single mom -- who has two kids, daughter Maya, 11, and son Levon, 7, with ex-husband Ethan Hawke -- has had her share of meltdowns on her quest to do the right thing for her children.

While Thurman's fiance, financier Arpad Busson, lingered nearby, the actress talked to iVillage about how parenting has changed her, her struggle to forgive herself for not always getting it right, and the disastrous brown sugar incident at one party she threw for Levon.

What attracted you to the character of Eliza in Motherhood?

[Writer-director] Katherine [Dieckmann] articulated an experience that I felt that I alone had: a time when your children are very young and you find yourself as a person, and find yourself as a mother. There is nothing in the world more healing than to realize that it’s a shared experience -- the imperfections, the realness of the woman, the sincerity and the genuine love that she infuses mothering with. And, yet, it still includes the whole rest of it -- the passions, the frustrations, and unmet needs and ego and struggle with self-control, all these issues that don't go away when you become a parent.

What's changed now that your kids are older?

When the kids were very little, and all the labors and the hormonal thing, the labor of the pregnancy, I felt like I turned into a plant. I felt like the skin on my body no longer had salt on it. It's slowly reemerging back and feeling the essence of being a woman independent of your responsibility of mothering, and still being a mother, and recognizing the fault line between you and your expectations and somehow forgiving yourself, which is really hard to do. I guess I should try it and see how hard it is! [laughs].

Do you feel you have more perspective now?

With my daughter, I have to remind myself that you're raising them to be women, not little girls. Not to take away the child but you have to nurture their independence and see that they have survival skills so that they can go on with their lives. It's the saddest thing to be left, to have your heart broken that way. But if that doesn't happen, you've made a mistake because you've handicapped a person, not helped them along.

Motherhood climaxes with a child's birthday party -- have you had a similar experience?

I get caught up in the birthday party situation. I had a pirate party for my son and I designed this cake myself. I drew it on a napkin: There's a beach and the boat in the water and I had to get it right. And the baker used brown sugar instead of cookie crumbs to make the sand. So I produced this incredible birthday party under this pressure that my life depended on it, that my entire definition as a person depended on it that day. Cut the cake up, pass it around, and one boy turns to my son and says, "Brown sugar, that's disgusting!" And my son, who I'd hyped up with so much effort, just fell apart crying. What the hell are you going to do about it? I try too hard. In the end, there's all the hysteria, the desperate effort, that create an overdoing, so that makes someone else resentful, so that they to turn to a 6-year-old and say, "Your cake sucks." Of course, I overdid it a bit. As my mother said, my name should be "Overdo It Uma." I never feel like I've done enough.

Get more Uma Thurman scoop in our exclusive video interview with the Motherhood star.