“I DO … UNTIL I DON’T”

** 1/2

(R, 1:43)

At its gooey center, “I Do … Until I Don’t” is like vanilla cake. It is sweet, but generally there’s nothing that memorable about it. Writer-director Lake Bell’s examination of marriage as a tradition does little to go past the norm when it comes to the arguments about whether it is good or bad to tie any kind of knot.

There’s nothing that new in the script, but what Bell has cooked up would be a sufficient serving of cinema if the debate was the only ingredient. What gives her recipe for romantic fun a flavor boost is a first-rate cast that includes Ed Helms, Mary Steenburgen, Paul Reiser, Amber Heard, Wyatt Cenac and Dolly Wells. Each performer adds his or her own brand of silly seasoning to the mixture, and the product that was once vanilla develops some richness.

The way Bell uses the various combinations of characters keeps the story fresh and makes a plot that has been a staple of Hallmark movies for years come across with some extra layers of depth, warmth and humor. It’s not as complicated a blending of tales of love as a masterful production like “Love Actually,” but it does have enough mixing and matching to be interesting.

Bell not only wrote and directed the film, but she also stars in it, playing Alice, the loving wife of Noah (Helms). Alice and Noah are never apart as they not only share a home life, but also run a floundering business where they sell window blinds. Their good life begins to suffer because of financial problems with the business and failed efforts to start a family.

There’s also a little tension because Alice believes Noah has feelings for her younger sister, Fanny (Heard), who lives a Bohemian lifestyle with Zander (Cenac). Alice is threatened by both her sister’s beauty and the sexual freedom her sister is always promoting.

All of this comes out when a British documentary filmmaker comes to Vero Beach, Fla., where the couples live. Vivian (Wells) is looking for subjects for her latest film expose, which will show how marriage is an archaic idea and couples should only have to enter into a contract for seven years. It doesn’t matter if the couples believe her theory; she just needs chaos in front of her camera.

Alice and Fanny agree to be part of the filming along with Cybil (Steenburgen) and Harvey (Reiser), a couple who have been married so long they may be reaching a point where an escape clause in a marriage contract sounds good.

The moviemaking icing on Bell’s work is the inclusion of the making of the documentary as part of the story. This is a great strand that runs through the film, energized by the way Wells pompously pushes her agenda to get the results she wants and not what naturally occurs. Bell also shot the documentary footage, and it reflects all of the imagery that has become so familiar in the work of iffy documentarians.

Wells captures the blend of wackiness and ego that has made documentarians like Michael Moore bigger stars than their productions. At one moment Wells can be skillfully arguing her points about marriage and then moments later show so much insecurity that she needs to spoon her assistant.

Bell has created two movies that are as different as vanilla and chocolate. The main story has a workmanlike quality that becomes more entertaining because of the way the cast members give their characters extra depth. There’s nothing new about a jealous wife or a man reaching a midlife crisis except when it is actors like Bell and Reiser who are behind the roles. Both have an instant likability that keeps them on the good side of an audience no matter what they do.

If left unchecked, Helms can slip into manic bouts of comic hysteria. Bell directs him to a very sweet performance while still allowing him to be funny. At the same time, she pulls Steenburgen — who has been known to fade into the background — to the front, making this one of her better performances in years.

The best thing about “I Do … Until I Don’t” is that it’s an old-fashioned love story. That sounds like an insult because these days most attempts at movie romances either get torpedoed by a painfully bad performance (think most Katherine Heigl movies), get drenched in the kind of sentimentality that has made Nicholas Sparks rich or give in to heavily mature themes.

Bell doesn’t take a lot of chances, and the fact that she plays it so safe is why the movie originally looks to be vanilla in design. But her commitment to her story, the actors selected to give that story life and a wicked sense of humor about documentaries sprinkle the film with some tasty moments. In this case love means never having to say you’re sorry when the end result is sweet and funny.