If you're hoping to get your cookbook picked up by a major publisher, get an agent first. They don't cost anything out of pocket, and they will certainly get you a multiple more than the 15% they take.
Find an agent by sending your proposal to a long list of them. Where to get that list? Authors thank their agents on the acknowledgements page; pull your best cookbooks down off the shelf and make that list.
You are at your most powerful when your proposal is done and you are shopping it around—don't take an editor's premature interest in you to the bank. Editors are motivated by great cookbook ideas but also by the fear that their competitors will grab you before they do. Keep hope alive, don't shut anyone out, but ideally you want interest from multiple editors (managed by your agent). Also, ask the tough, convention-bending questions now, when you're powerful, before inking the deal: once you sign, you transform into a burden to the winning editor and persona non grata to the underbidding editors.
Every step in the process can be outsourced. Writers for the proposal and manuscript, recipe-developers to transform your stained binder of material into something publishable, testers to make sure the recipes work, art directors to run the photo shoot—you name it, there are plenty of talented and eager freelancers out there who would be thrilled to work on your project and won't charge an arm and a leg. In fact, if it's the difference between getting the cookbook done well and it never happening at all, spending money on publishing teammates may be the best value in the world.
Once you get the book deal, don't fool yourself into thinking you can find the time to develop the cookbook interstitially, between work and family obligations: commit yourself to getting it done in a cohesive, sustained way that allows you to immerse yourself in the world of your book. Take a sabbatical, ruin your summer, just find the weeks and months necessary to make it great—it takes less time ultimately to do the hardest work, the recipe development, all in one marathon.