Elizabeth Halen cooks, bakes, and owns a food business at Reading Terminal Market - what she calls "the best grocery store in the city" - but many days, she concedes, she is just as clueless about what to make for dinner as you are.

She and her boyfriend, Jason Wagner, were batting around ideas for years - not only about specific food items but about what the market needed. "I know all the wonderful things our purveyors have here," she said.

They decided that the market needed something to better tie together its fresh-food purveyors. What happens after you pick up pork chops at Martin's, or salmon at John Yi's, or a bunch of carrots at Iovine's? You take it home. What is the next step?

Halen, who owns Flying Monkey Bakery, will join market officials on Thursday to announce the signing of a lease for Condiment, a stand at the western end of Center Court, where Mezze was.

Condiment, targeted to open around Memorial Day, will sell a wide line of house-made sauces, dressings, and condiments, including fresh butter and mayonnaise churned and whipped on premises and combined to order with fresh herbs and other ingredients. Butter will be compounded much as it's done with ice cream at Cold Stone Creamery - on a refrigerated marble slab.

Halen expects customers to buy their meat, fish, and vegetables at various market stands, and have Condiment staff vacuum-seal the food in a plastic bag with a marinade. "You finish your shopping and it's marinading," Halen said. "That part of the work is done for you."

She will have photo-flled "look books" with dinner ideas, to allow people to create a shopping list and buy ingredients within the market to make preparation easier.

She also will sell pie dough, biscuit dough, puff pastry, and dessert sauces, including chocolate ganache and seasonal fruit preserves. Croutons and bread crumbs, too, that are "not full of sodium."

Baking was her calling. Halen, born in New Hampshire but raised all over, was a Ph.D. candidate (Temple sociology) who enjoyed teaching but didn't like what she called "the rat race of academia." All the while, she reported to work at 5 a.m. at Flying Monkey - then a cupcake stand - and at 10 a.m. headed to a second job at A Full Plate Cafe in Northern Liberties. When Rebecca Michaels decided to sell Flying Monkey, Halen saw opportunity. Goodbye, Temple.

She took over Flying Monkey in October 2011 and turned it into a full-service bakery that expanded further a year later when the market renovated its Avenue D. Her line now includes signature cakes and whoopee pies from family recipes.

"I'm such a food person," she said. "I like to cook real food, and this is an opportunity to showcase this set of skills that I have. It's actually an extension of the way I live my life at home. My boyfriend [who works in the market at Valley Shepherd Creamery] and I don't buy butter. We buy cream here from the Fair Food Farmstand and make our own butter, like a throwback.  ... Nothing is going to have preservatives, and as much as possible, we'll source our ingredients within the market."

Wagner and a third partner, Ari Saxe, will run the counter most days.

The market's tenant roster had been firm for a while.

Anuj Gupta, the general manager, said he had a stack of applications on his desk that had piled up before he started working there. "There was a lot of the same thing - not many that stood out," he said.

Near the bottom, he found Condiment, "and I did a double-take. I asked myself, 'Is this a real concept?' And then I asked, "Is this our Elizabeth Halen?'"

He thought about it a bit, and said he decided, "It's hard to come up with a concept that ties into our theme better than this. It refines the shopping experience and ties the shopping experience better."