Make the Crack Sauce: Combine the ranch dressing, mayonnaise, sriracha, and garlic powder in a small bowl and whisk until completely smooth. Taste and adjust the sriracha level based on your heat preference. Set aside in the refrigerator until assembly.

Start the Caramelized Onions: Melt 2 tablespoons butter in a skillet over medium heat and add the sliced onions with 1/2 teaspoon salt. Stir to coat every strand with butter and spread them evenly across the pan. Stir every 3 minutes.

Continue Building Onion Flavor: After 8 minutes, sprinkle the brown sugar over the onions and stir well. Reduce heat to medium low if they start to darken too quickly. Cook a total of 15 to 18 minutes until deep golden brown and jammy.

Portion the Beef: Divide the cold ground beef into 4 equal portions of roughly 6 ounces each using a kitchen scale. Roll each portion into a loose ball without compacting the meat too tightly.

Preheat the Cast Iron: Place your cast iron skillet over high heat for a full 5 minutes until it begins to smoke lightly. Add 1 tablespoon vegetable oil and swirl to coat.

Smash the First Patties: Place 2 beef balls in the skillet leaving 4 inches between them and immediately press each flat with your meat press or the bottom of a heavy pan. Press firmly for 10 seconds to achieve 1/4 inch thickness. Season the top with salt and pepper right away.

Develop the Crust: Let the patties cook undisturbed for exactly 2.5 minutes without pressing or moving them. Watch the edges where you will see the brown crust climbing up the sides.

Flip and Add Cheese: Slide your metal spatula under each patty with a firm scraping motion and flip in one confident motion. Immediately place one slice of cheddar on each patty. Cook the second side for only 1 minute.

Toast the Buns: While cheese melts, spread softened butter on the cut sides of each brioche bun and place them cut side down in a second skillet over medium heat. Toast for 90 seconds until golden brown.

Cook Remaining Patties: Transfer the first two patties to a plate and repeat the smash, sear, flip, and cheese process with the remaining two beef balls.

Assemble the Burgers: Spread a generous tablespoon of crack sauce on both cut sides of each toasted bun. Place the cheesy patty on the bottom bun and top with a heaping spoonful of caramelized onions. Add pickle slices if using and close with the top bun.

Rest and Serve: Let the assembled burgers rest for 2 minutes before serving. Cut in half if desired for easier eating. Serve immediately.