Atulea Like List
Vince Shi and Kathy Wang's stylish Capitol Hill tea shop has put their own twist on hot chocolate by mixing it with genmaicha (brown rice green tea) and topping it with mini marshmallow bits.
Capitol Hill
Pickup, delivery, dine-in

Chocolati
This Seattle cafe specializes in artisan chocolate, and their unparalleled hot chocolate is rich and creamy and comes in a variety of flavors, from peanut butter to salted caramel to Aztec. The "Dark Vader" (raspberry and dark chocolate) is an especially popular menu item.
Various locations
Pickup, dine-in

Chocolat Vitale Like List
Chocolat Vitale serves up "a sinfully rich" hot chocolate that finds its origins in a distinctly European style of hot chocolate. They also offer small-batch chocolates, wines, and specialty teas.
Ballard
Pickup, delivery

Fran's Chocolates
This family-owned chocolate company's 68% single-origin Venezuelan drinking chocolate is extra luxurious.
Various locations
Pickup, delivery

Hot Cakes
The molten chocolate dessert emporium will let you order their luxurious Valrhona sipping chocolate with or without the booze of your choice.
Ballard, Capitol Hill
Pickup, delivery, dine-in

Indi Chocolate Like List
The small-batch artisan chocolatier's cafe serves single-origin drinking chocolate, which can be customized with your choice of milk and with add-ons like lavender cacao syrup and chai marshmallows. The online store also offers their drinking chocolate in cube form on a stick—stir it into a mug of warm milk to recreate the drink at home.
Pike Place Market 
Pickup, delivery

Le Pichet Like List
If a cup of thick, rich, Parisian-style chocolate chaud topped with whipped cream is what you're after, hightail it to Le Pichet in Pike Place. Owner Jim Drohman has also shared the recipe on his blog so that you can recreate the magic at home.
Capitol Hill 
Pickup, delivery, dine-in

Oddfellows
Big, fluffy house-made marshmallows float atop Oddfellows's house hot cocoa.
Capitol Hill
Pickup, dine-in

Peony Bakery Like List
This small bakery business run by an elementary school teacher sells hot cocoa bombs made with house-made triple chocolate, cocoa powder, and mini marshmallows. They also have flavors like matcha, taro, hojicha, and "winter snowflake" (peppermint white chocolate mocha filled with edible glitter, snowy sprinkles, crushed peppermint, and marshmallows).
Belltown
Pickup

Rey Amargo Chocolate Shop Like List
This cafe, started by a chocolate company based in Jalisco, Mexico, serves a dizzying array of high-quality drinking chocolates, including classic hot chocolate, iced drinks and frappes, Aztec- and Mayan-inspired versions, and French and Spanish hot chocolate.
Capitol Hill
Pickup, delivery, dine-in

Shug's Soda Fountain
Old-timey soda shoppe Shug's Soda Fountain puts their signature twist on hot cocoa with a Gran Gran's Cocoa float, with house-made cocoa, a scoop of vanilla ice cream, whipped cream, and a dusting of cocoa powder. Add Bailey's, Kahlua, or Frangelico for extra coziness. For those who prefer the traditional, there's also regular hot cocoa with housemade marshmallows or whipped cream.
Downtown
Pickup, delivery, dine-in

Theo Chocolate Like List
The local chocolate company's signature dark drinking chocolate is the real deal, made with 55% single-origin dark chocolate. A peppermint variation is also available.
Fremont
Pickup, delivery