The former Cross Keys pub in St Albans has the capacity for around 120 guests - half of which can be held in the 60-cover fine dining restaurant.
The concept focuses on rustic grilled meats at a mid-scale price point served from an Inka charcoal grill in the open kitchen headed up by well-known local chef Steven Kitchen.
Speaking to BigHospitality, Marler said the venue joins The Old Manor Bar & Restaurant in Potters Bar in his portfolio but may not be the last site in the Heritage Inns business. The industry entrepreneur hopes to run around five venues in total.
While the traditional British venture in Potters Bar, which Marler has run for around a decade, and Baroque have different food concepts what they have in common is being former pubco-owned sites which the big companies decided were no longer profitable.
"They are good venues in maybe not prime locations where you have to polish hard to get the thing to shine. Small independents are usually a lot more focused on the individual site - the shine comes and so do the people – it is pretty simple."
Marler's first pub was an eponymous venue in north London's Muswell Hill which was bought by Tim Martin who used the business to launch the chain that became J D Wetherspoon.
“I have always been interested in the one-offs. Oddly enough the pub that we bought to make Baroque out of was an old J D Wetherspoon pub. So maybe it has come full-circle," he said.
After an initial soft launch period, Baroque will officially open this week serving all-day food including breakfast and bar snacks. It will also combine a restaurant with a 'high end' bar serving mixologist-prepared cocktails.
As well as the Shepherd's Bush Empire, Marler was behind the expansion of popular Camden pub The World's End. He said he expected the growth of successful smaller operators to continue in the future.
"The pub market will become more fragmented into smaller batches of better-run pubs for people. You might see a third of the units that are currently changing hands either closing or being re-constructed into more intensely-operated outlets."
"If you get your systems in place good food is relatively easy to do and very enjoyable when you get it right. It still thrills me in my 59th year."
The Baroque Café Bar & Grill is currently looking to fill a range of vacancies including managers and chefs - full details on the advertised posts are available within the jobs section of BigHospitality .