Part-time pastry chef at a popular medium-sized-bistro - how much to charge?

[editor@bcdisabilities.com]

Med.-high-end pasta place does great entrees but terrible desserts. I have no pro exp but make fabulous French tartes, galettes with locally-grown seasonal fruit plus a variety of cakes and so on. Each might easily be paired with a dessert wine/liqueur, which would allow restaurant to reclaim lost sales. Ideally, I'd like to come in early a.m. several times a week to prepare evening dessert menu. How do I come up with and present an attractive offer?