Lisa Patterson studied engineering in Germany, where structure extends even to that most traditional of German foods, the gingerbread house. But Patterson, 33, recently switched career angles to open a sandwich shop in Middleburg based around that most unstructured food, the marshmallow.

Mello Out, located in the cool, stone nether region of one of the upscale village's early 19th-century buildings, was born because Patterson's daughter was: Patterson wanted to be with her baby, not stuck on the road with the commuting hordes. She had been making marshmallows for gifts since she was 6, and a trial run at the Middleburg farmers market showed her that people still had a soft spot for the sweet confection of their childhoods. So with the help of her husband, Tom, Patterson opened her takeout shop in April.

Of course, Patterson's "marshmellos" are not the plebian numbers that you stabbed with a stick and singed into blackened goo in the campfire as a kid. No, her marshmello is a more refined creation offered in flavors of peppermint, lemon, orange, vanilla and almond and sold in packages of four for $4. They are sold one at a time, too, plain ($1) or dipped in chocolate ($1.50).

Of course, a business cannot survive by marshmallow alone. Mello Out's real bread and butter is its sandwiches and salads, none priced higher than $6.75. The basement cafe, which has a smattering of patio tables with umbrellas but no in-house seating, specializes in paninis, which are not available anywhere else in Middleburg, Patterson says. A Flying Pig -- Black Forest ham, apple butter and cheddar cheese on walnut raisin bread -- is $5.50. Breakfast paninis show a heavy Nutella influence, acquired in Patterson's time as a student in Europe. A Monkey Business ($3.50), for example, is Nutella and banana on brioche.

The shop's menu is rounded out with "Cosmic" cookies, cupcakes and other desserts from a local baker and a cold and hot nonalcoholic drink selection. A favorite sip now that mornings have a nip is Italian hot chocolate with peppermint marshmellos. A liquid peppermint patty -- can there be a sweeter way to start the day?

Mello Out, 2 E. Federal St., Middleburg. Open daily 8 a.m. to 5 p.m. Call 540-687-8635.

-- M.J. McAteer

M.J. McAteer is The Washington Post's letters editor and a freelance writer.

Lisa Patterson with some of her marshmallow creations.