By the time the luxe Eleven on the River opened its doors about a year ago, most of the custom units in Minneapolis' tallest residential building were move-in ready. Only the 13 penthouses on the upper floors remained shells, to allow their owners to build them out as they wished.

Recently, the team behind the riverfront tower decided to pivot and make several of the penthouse units turn-key.

"We might have people coming from 7,000- to 10,000-square-foot homes. We wanted them to walk in here and say, 'There's nothing here that's missing,' " said listing agent Kevin Mullen. "We thought, people really have to see it to believe it. This is built for everyday living and doesn't compromise their ability to entertain, both the private and public spaces are there."

Now, the first of those penthouses in the sleek white Mill District tower has hit the market for a cool $6.49 million. At just over 3,800 square feet, the three-bedroom, four-bathroom unit takes up half of the 36th floor and comes with a "trifecta of views" of the Mississippi River, the downtown skyline and Gold Medal Park.

Luxury 'home in the sky'

To design and build out the penthouse, interior designer Brooke Voss and luxury custom builder John Kraemer & Sons lead the charge.

John Kraemer said this type of project is a first for his company and he was glad to be a part of it. "We build mostly single-family homes on Lake Minnetonka and Edina. We see the energy coming back to Minneapolis and we thought it was just a really great opportunity," he said.

With the penthouse, Kraemer's firm took the same approach it does when building single-family homes.

"It's building a luxury custom home, but in the sky with the same finishes and materials and high-end design and architecture that we would see in the homes that we're building out on the lake," he said.

White oak can be found in the millwork, entryways and wide-plank flooring. Luxe finishes include high-end appliances and quartz countertops (including in a scullery off the kitchen). In the owners' suite bathroom, marble is used for the flooring and surround.

At more than twice the square footage as the average condo at Eleven, the penthouse unit looms large.

"Here we have a really large entertaining space where you could have 30 to 40 guests comfortably in here," Mullen said.

An outdoor space just past the kitchen and dining room — one of two 14-by-24-foot terraces — acts as a spacious open-air living room and is meant to be enjoyed well into the cold weather months.

"We were one of the first [condo] buildings in Minneapolis to do integrated heat to elongate the use," Mullen said.

Hidden spaces

The long hallway that leads to the unit's private spaces is no afterthought, either. It's outfitted with floor-to-ceiling built-ins plus a hidden access panel to the back entrance.

"We decided 'Let's just make it a secret entry,' which we do in other homes that we've built," Kraemer said.

At the end of the hall, the owners' suite has its own coffee bar area and an oversized, walk-in closet with high-gloss built-ins and display shelves. There's also an en suite with a large walk-in spa shower and a soaking tub, from which it's possible to see all the way to the St. Paul skyline. The primary bedroom suite also has its own terrace and library.

The second and third bedrooms also get the royal treatment, with floor-to-ceiling built-ins and private bathrooms with high-end finishes.

Even "with all of the bedrooms, you can still get all the benefits of privacy and have proper en suites without compromising," Mullen said.

Five-star amenities

Eleven was designed by New York starchitect Robert A.M. Stern, who's known for creating buildings that complement its neighbors, such as the Foshay Tower, in this case.

Building amenities include an outdoor lounge with a lap pool, a sports court, fitness center, billiards room and golf simulator. It also houses a library, board room, entertaining spaces (including a demo-style kitchen, formal dining and lounge areas that can be booked for private parties) and round-the-clock concierge services.

Mullen said 100 of the 120 homes have been sold. As for the remaining 12 penthouses? "We plan to continue to build out homes at this level as we continue to sell," he said.

Kevin Mullen (kevin.mullen@lakesmn.com, 612-340-9000) of WMG Partner at Lakes Sotheby International Realty has the $6.49 million listing.