Preheat air fryer for 5 minutes on hottest setting.
In the meantime, combine all ingredients EXCEPT for ketchup in a medium mixing bowl.
Divide beef mixture into 4 equal parts and shape each into a ~4½ inch patty, making an indention in the middle with your thumb to prevent too much shrinkage.
Carefully place burger patties into hot air fryer basket. Lightly brush the top of each with ketchup or BBQ sauce.
Air fry at 370°F for 5 minutes. Flip burgers, brush other side with ketchup/BBQ sauce and then finish air frying for 3-6 minutes, until done.
If using cheese, immediately place on cooked burger patties and place back in switched off air fryer for 1-2 minutes, until melty. Serve as desired - we like them on buns with all of the burger trimmings.
Notes
Ingredient notes
Ground beef: 80/20 beef will yield juicier burgers, but I have also tried these with 90/10 beef and they were perfectly fine. Brushing them with ketchup or BBQ sauce definitely helps to keep them from drying out!
Seasoning: The seasoning added is what I love in burger patties. Nothing is mandatory (I know the parsley especially is highly personal, as I have had endless discussions about it with family members ?) and if you prefer your burger patties seasoned with just salt and pepper, you are absolutely free to do so!
Ketchup/BBQ sauce: I highly recommend using this to keep the burgers from drying out, and to add a little extra flavor. If you don’t like ketchup or BBQ sauce at all, at the very least brush your burgers with a little vegetable oil.
Recipe tips
Make sure to fully incorporate the spices into the meat, to ensure even seasoning of all patties.
On the other hand, only mix as long as needed. If you overwork the meat mixture, the burgers may come out too crumbly.
Do not skip making an indention in each patty, it really does help to keep the patties from shrinking too much.
The patties tend to thicken and shrink a little during cooking, so do not be afraid to make them about 4.5 inches in diameter.
Once patties are done, warm buns in the air fryer for 1-2 minutes (be careful so they don't burn! Split to toast in the air fryer, so they have no chance of touching the top heating element!). Serve patties on buns with lettuce, tomato, red onion, pickles and your favorite burger sauce.
Fries?
If you want to cook fries in your air fryer to go with the burgers, I recommend making the fries first (they take about 20 minutes, vs the burger's 10 minutes). Spread the fries on a baking sheet and keep them warm in a 170°F (75°C) oven (or on a "keep warm" setting, or on the lowest heat setting available) until the burgers are done. Unfortunately, you cannot cook fries and burgers in the same air fryer at the same time.Estimated nutrition does not include cheese or burger buns/toppings.