Preheat your oven to 175°C (350°F). Lightly grease a 9x13-inch baking dish with cooking spray.

In a skillet over medium-high heat, cook the ground beef while crumbling it with a wooden spoon. Add both packets of dry onion soup mix and stir to combine. Cook until the beef is no longer pink.

Drain the cooked beef mixture in a colander, then use paper towels or a clean dish towel to press down and squeeze out as much liquid as possible.

Unroll one tube of crescent roll dough and arrange it in the prepared baking dish, pressing the seams together to form a crust on the bottom.

Spread the drained ground beef mixture evenly over the crescent roll crust. Top with slices of American cheese, followed by a layer of chopped dill pickles. Drizzle mustard over the top.

Unroll the second tube of crescent roll dough and arrange it over the top of the casserole, stretching and sealing the seams to form a top crust.

Bake for 15-20 minutes, or until the top crust is golden brown and the cheese is melted.

Let the casserole cool slightly, then cut into squares. Serve warm with additional condiments like ketchup or mayo, if desired.