Divide the 1 lb ground beef into two equal portions and gently form into 2 patties about 3/4-inch thick. Press a slight dimple in the center of each patty to prevent doming during cooking. Season both sides evenly with 1 tsp kosher salt and 1/2 tsp freshly ground black pepper.

Cook patties

Heat 1 tbs vegetable oil in a heavy skillet or cast-iron pan over medium-high heat until shimmering. Add patties and cook without moving for 3–4 minutes until a brown crust forms. Flip and cook 2–3 minutes more for medium (adjust time for desired doneness). In the last 60–90 seconds, top each patty with 1 slice of sharp cheddar, cover the pan briefly to melt the cheese. Remove and rest on a plate.

Toast buns

Butter the cut faces of 2 hamburger buns with 1 tbs butter. In the same skillet (wipe excess fat if needed), toast the buns cut-side down over medium heat until golden, about 1–2 minutes. Remove and set aside.

Sauce

Combine 1/2 cup chipotle BBQ sauce, 1 tbs honey, and 1 tsp apple cider vinegar in a small bowl. Stir until smooth and taste; adjust honey or vinegar for balance. Keep warm or at room temperature until assembly.

Cheese & Toppings

Cook bacon

Place 4 slices honey-cured bacon in a cold skillet and cook over medium heat, turning occasionally, until crisp and caramelized, about 8–10 minutes. Transfer to a paper-towel-lined plate to drain. If bacon rendered excessive fat earlier, reserve 1 tbs fat in the pan for flavor (optional).

Prepare pickles

Lay out 4 pickle slices for assembly. Pat dry if necessary.

Onion Ring

Slice onion

Cut the half onion into 1/2-inch thick rings and separate into individual rings. Discard the center smaller pieces or save for another use.

Make batter

In a bowl whisk together 1/2 cup all-purpose flour, 1 tbs cornstarch, 1/4 tsp baking powder, and 1/4 tsp salt. Gradually whisk in 1/2 cup cold sparkling water until a smooth batter forms. The batter should be slightly thicker than pancake batter; adjust with a tablespoon more water or flour as needed. Keep batter cold.

Fry onion ring

Pour 2 cups vegetable oil into a medium saucepan to a depth of about 1 1/2 inches and heat to 350°F (175°C). Working in a single layer, dredge onion rings in a light dusting of flour (optional), dip into the cold batter, letting excess drip off, then carefully lower into the hot oil. Fry until golden brown and crisp, about 2–3 minutes, flipping once. Use a slotted spoon to transfer to a paper-towel-lined tray and sprinkle with a pinch of salt. Keep warm or reheat briefly in a 325°F oven while assembling burgers.

Assembly

Spread a generous tablespoon of the chipotle BBQ sauce onto the bottom half of each toasted bun. Place the cheddar-topped patty on the sauced bun. Add 2 slices of honey-cured bacon over the melted cheese. Top bacon with 2 pickle slices. Spoon an additional 1–2 teaspoons of sauce over the pickles if desired for extra flavor. Crown the burger with the top bun and press gently.

Place one crispy onion ring on top of the bun as a garnish so it sits over the top (or serve the onion ring skewered to the burger with a toothpick). Serve immediately.