Mind the basil-mayo splooge in this otherwise picturesque veggie burger from Mildred’s restaurant in London’s Soho. Splooge aside, this was a close-to-flawless burger from a restaurant I have long-regarded as an expert in veggie burgers.

I went to Mildred’s this afternoon to conduct research for a new project I’m working on: my quest for the ultimate veggie burger. My quest even has a home: ultimateveggieburgers.com.

What do I mean by “ultimate”? I’m looking for flavour, texture, balance, and an absence of mushiness or crumbliness. I want a burger that isn’t based on bread crumbs or jumbo oats, but rather, fresh vegetables or hearty nuts and legumes. My perfect burger will also omit processed ingredients such as TVP, vital wheat gluten or Quorn.

My goal is to find a recipe so that I can create the ultimate veggie burger in my own kitchen. As part of my research, I will not only try various veggie burger recipes recommended to me by friends, chefs, and readers, but I will also go to restaurants and see how the pros do it. And so, this is how I arrived at Mildred’s.

Before today, I’d only been to Mildred’s once a couple of years ago. They have an always-changing “burger-of-the-day” on their menu, served with lettuce, tomato, relish, and basil “mayo”, which I later learned was not mayo at all, but rather a soy-based imitation (I had no idea!). The burger is vegan, too, and on that particular day, it was made up of shredded beets, peas, fennel seed, spring onion and pumpkin.

Mildred’s beet-based burger was phenomenal, and stands out as one of the best veggie burgers I’ve ever had. So today I returned to see if other burgers stood up to the test.

Today’s burger-of-the-day ways a kidney bean and olive burger. “A strange combination,” I thought. But of course, I ordered it without hesitation, and was very glad that I did.

The olives gave the burger a rich, savoury flavour that worked surprisingly well with the kidney beans. I also enjoyed the occasional whole kidney bean hiding in the burger – this seems to be a hallmark of Mildred’s, whose previous burger was flecked with whole peas.

My only reservation about the burger was this: I missed the texture of the shredded beet. In fact, there was very little texture in this burger at all, but it made up for it by being well seasoned, pleasantly moist, and not at all mushy.

So the question remains – what is this burger made of? Surely there is more to it than kidney beans and olives.

To find out, I’ve sent an email to Mildred’s head chef, Daniel Azevedo, and await his response with bated breath. In the meantime, the weekend is coming, and is the perfect opportunity for my next experiment.

Following Mark Bittman’s excessively corny recommendation, I am turning to something completely different:

If you have a suggestion for the “ultimate veggie burger”, please visit ultimateveggieburgers.com and click “Suggest a burger.” I promise to try every veggie burger suggested to me, but do mind the rules, and try to be patient – one can only make so many veggie burgers!