Prep the zucchini. Heat the oven to 400°F (200°C). Trim the ends of each zucchini, slice lengthwise, and scoop out the centers with a spoon, leaving about 1/4 inch shell. Reserve about half the scooped flesh, finely chop it, and pat it dry.

Par-bake the boats. Brush the zucchini shells with olive oil, season with salt and pepper, and place cut side up on a baking sheet. Bake for 8–10 minutes until just tender. This keeps the boats from getting soggy later.

Brown the beef. In a large skillet over medium-high heat, warm a bit of oil. Add the beef and cook, breaking it up, until browned and no longer pink. Drain excess fat if needed, leaving about 1 tablespoon for flavor.

Add aromatics. Stir in the diced onion and garlic. Cook 2–3 minutes until softened and fragrant. Add the chopped zucchini flesh and cook another 2 minutes to release moisture.

Build the burger flavor. Stir in tomato paste and cook 30 seconds. Add Worcestershire, ketchup, and mustard. Season with salt and pepper. Fold in the chopped pickles and half the shredded cheese. The mixture should be savory, slightly tangy, and not watery.

Stuff and top. Spoon the beef mixture into the par-baked zucchini shells, packing it in. Sprinkle the remaining cheese on top.

Bake to finish. Return to the oven and bake 10–12 minutes, until the cheese melts and the zucchini is tender but not mushy.

Add toppings and serve. Top with extra pickles, a drizzle of ketchup and mustard if you like, diced tomatoes, shredded lettuce, or a few sesame seeds for that burger vibe. Serve hot.