Tangy Double-Stacked Beef Burgers

While potatoes cook, peel, then cut onion into 1/4-inch slices. Heat a large non-stick pan over medium heat. When hot, add 1/2 tbsp oil (dbl for 4 ppl), then onions. Cook, stirring often, until onions soften slightly, 3-4 min. Add 1 tsp sugar (dbl for 4 ppl) and season with salt. Cook, stirring occasionally, until dark golden-brown, 3-4 min. Remove the pan from heat. Transfer onions to a small bowl, then set aside. Carefully wipe the pan clean.

While onions caramelize, combine beef, panko, half the Dijon, 1/4 tsp salt and 1/4 tsp pepper (dbl both for 4 ppl) in a medium bowl. (TIP: If you prefer a firmer patty, add an egg to the mixture! For 4 ppl, add 2 eggs.) Form into four 4-inch-wide patties (8 patties for 4 ppl).

Heat the same pan (from step 2) over medium-high. When hot, add patties to the dry pan. Pan-fry until cooked through, 4-5 min per side.** (NOTE: Don't overcrowd the pan; cook patties in 2 batches if needed!)

While patties cook, finely chop pickles, reserving pickle juice. Roughly chop parsley. Stir together half the pickles, ketchup and 1 tbsp mayo (dbl for 4 ppl) in another small bowl. (NOTE: This is your tangy mayo!) When potatoes are fork-tender, drain and return them to the same pot, off heat. Add parsley, reserved pickle juice, remaining pickles, remaining mayo and remaining Dijon. Season with pepper, then gently stir to coat.