Burgers were never really Neil Perry's plan to help his new restaurant through lockdown, but where there's a wood-fire, there's an opportunity to make Sydneysiders happy with grilled meat between bread.

"We were already lighting the fire to cook chicken alla cacciatora and sear beef fillets for the Neil Perry at Home packs, so I said to the team, 'let's just get a few burgers out at the same time'," says the former Rockpool chef, who was set to launch Double Bay fine-diner Margaret the week Sydney's current COVID-19 lockdown was announced.

"It was crazy. We made 100 burgers the first day and sold out by 12:15pm. Now we sell about 250 burgers at lunch [Wednesday to Saturday], plus 100 sandwiches on top of that."

While Perry's "at home" meals available through delivery platform Providoor reflect the kind of produce-driven cooking his restaurant will offer when it can welcome guests, right now Margaret is also Australia's most high-profile tuckshop.

"I was eating chip sandwiches all last week, so we put a butty with sauce on the menu and it flew out the door," says Perry.

The chip butty joins a chicken katsu sandwich and luxe salad roll with ham, provolone, lettuce and a thicket of grated carrot.

Meanwhile, the Margaret burger – $25 with chips – features full-flavoured brisket and chuck from CooperTree Farms retired dairy cows. It's the bellwether of a food trend Sydney hasn't experienced at such high levels in years: fine-dining chefs flipping burgers.

Lockdown has led to Potts Point's Bistro 916 stacking a double cheeseburger; Poly is serving a takeaway works burger complete with beetroot and pineapple in Surry Hills, and Stanmore's three-hatted Sixpenny is frying a fish burger special for its pop-up general store.

Just this week, Anna Moretti, a chef de partie at Bennelong, launched a burger side-hustle in collaboration with Bondi Liquor Co, Waverley Council's first licensed distillery. The O'Brien Street gin joint opened its bar to the public only a month before lockdown.

"It's nice to just get busy and creative again," says Moretti, who has taken over half the venue with her flat grill and fryers. "As a chef, I'm used to working long hours at a fast pace – not being stuck at home."

Bondi Liquor is open Thursday to Sunday for takeaway cocktails and Moretti's burger creations, such as a parmesan and truffle number with tarragon mayo, and a vegan-friendly option made with broad beans and chickpeas.

BYOB (build-your-own-burger) kits have also taken off during lockdown. Boxes filled with buns, patties, cheese, sauce and fresh fillings are available for delivery from Pub Life Kitchen in Ultimo, Vic's Meat Direct, Chebbo's food truck and Burger Head in Penrith and Botany.

"We took 800 orders for our Big Mac-inspired kit this week," says Burger Head co-owner Tim Rosenstrauss, who also provides live cook-along videos over Instagram every Thursday for customers ordering the box.

"My business partner Josh [DeLuca] and I host the cooking sessions. It's a bit of fun even if it's not always the most professional production – we also play a drinking game that involves having to take a drink every time one of us says the word 'burger'."

Orders close on Tuesday for Burger Head's sixth lockdown box, a $35 collaboration with Bar Luca which has locations in Darlinghurst and Parramatta, plus a cult following for its "Blame Canada" burger loaded with maple bacon, fries, cheese curd and gravy.

"There's definitely less people venturing out for takeaway this lockdown compared to last year's," says Rosenstrauss. "While our two stores are down in sales, these boxes are helping us to keep going."

Five more great burgers for lockdown

American pattie purists will tell you that a burger must contain ground meat, preferably beef, and a bun filled with anything else is technically a sandwich. But Australia largely nixed that rule decades ago – wagyu, duck, fish or halloumi, Sydney's burger choices are delicious and many.

Baba's Place Samk-et-Harra (Lebanese Filet-o-Fish)

A hand-crumbed riff on McDonalds' fish sanga featuring pink ling, pickles, chimichurri and tahini tartare. Pair it with fries seasoned by garlicky toum salt at Marrickville's good-time Lebanese takeaway, also home to beaut cherry-glazed kafta. Takeaway only Thursday to Sunday. Call 02 9090 2925 to order.

Bistrot 916 Duck and Cheese Burger

If it looks like a duck burger, and tastes like a duck burger, it's probably from Sydney's most popular new bistro. In truth, with taxi-cab-yellow cheese and a crumbed puck of duck, the burger looks a lot like a Filet-o-Fish too. A $38 duck and cheese meal comes with fries and drink options such as a negroni spritz. Available for pick-up in Potts Point from 5pm until sold out, Thursday to Saturday. Order from bistrot916.com.

Icebergs Dining Room and Bar Iceburger

A no-funny-business burger starring beef, a soft bun, special sauce, lettuce and tomato. Full marks for both taste and name. This lockdown is the first time Maurice Terzini's Bondi flagship has delivered food in its 19-year history, so you may as well make the most of it and include a chocolate tart with the order too. Order online through Providoor for next-day delivery across most of NSW.

Mary's Mary's Burger

If there was a Mount Rushmore of Sydney burger pioneers, Mary's co-owners Jake Smyth and Kenny Graham would be chiselled in granite. (Not to mention Paul and Katina Zerefos, founders of Paul's Famous Hamburgers in Sylvania ) Mary's namesake burger is now eight-years-old and features buttery grass-fed beef, American cheese, oak lettuce and flavour-packed signature sauce. Pick-up from Mary's Newtown and CBD stores, and The Unicorn, Paddington. Delivery available via Deliveroo.

Sunset Diner Crispy Chicken Burger

Avalon's pastel pink American-style diner is looking after the Northern Beaches with salted caramel shakes, hot dogs and a crunchy buttermilk-brined fried chicken burger the size of a softball. Takeaway only Wednesday to Sunday. Order from sunsetdiner.com.au.