Adjust rack to middle position and preheat oven to 425 degrees. Wash and dry all produce. Peel and slice onion into 1/2-inch-thick rounds; separate into rings. (TIP: It’s okay if the rings break apart!) Thinly slice pickle into rounds. Halve lemon. In a small bowl, combine sour cream, ketchup, mustard, half the garlic powder (use all for 4 servings), and 1 tsp sugar (2 tsp for 4). Halve and toast buns.

Arrange bacon on a baking sheet. Roast on middle rack until crispy, 10-15 minutes. (TIP: Check your bacon periodically— thicker pieces may take a bit longer while thinner pieces will cook faster.) While bacon cooks, form beef into two equalsized patties (four patties for 4 servings). Season generously with salt and pepper.

Meanwhile, in a large bowl, whisk together tempura mix, 1/2 tsp salt (1 tsp for 4 servings), and 1/3 cup cold water (2/3 cup for 4) until smooth. (TIP: If mixture is too thick, add more water 1 TBSP at a time until it reaches a pancake-batterlike consistency.) Toss onion rings with Fry Seasoning; shake off excess. Stir into batter until fully coated; set aside. Heat a 1/3-inch layer of oil in a large, heavybottomed pan over medium-high heat.

Once oil is hot enough that a drop of batter sizzles when added to the pan, working in batches, carefully add coated onion rings in a single layer. (TIP: Place smaller rings inside larger ones to fit more in the pan per batch.) Fry, flipping once, until golden brown, 2-3 minutes per side. Transfer to a paper-towel-lined plate. TIP: If onion rings cool, add to a baking sheet; reheat in oven until ready to serve.

Heat a drizzle of oil in a second large pan over medium-high heat. Add patties and cook to desired doneness, 3-5 minutes per side. In the last 1-2 minutes of cooking, top each patty with pepper jack; cover pan to melt cheese.

In a second large bowl, toss mixed greens with a drizzle of olive oil and lemon juice to taste; season with salt and pepper. Spread top buns with a layer of special sauce. Fill buns with patties, bacon, sliced pickle, and one or two onion rings. Serve with salad and remaining onion rings and special sauce on the side.