Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper or a silicone mat for easy cleanup.
In a large bowl, very gently pick through your lump crab meat to remove any shells. Be super careful not to break up those beautiful lumps! Place the picked crab meat into a clean bowl.
In a separate, medium-sized bowl, whisk together the mayonnaise, panko breadcrumbs, chopped green onions, lightly beaten egg, Dijon mustard, Worcestershire sauce, Old Bay seasoning, and lemon juice. Mix until everything is just combined.
Now, add the wet mixture to the bowl with the crab meat. Using a rubber spatula or your hands, gently fold the wet ingredients into the crab meat. The key word here is GENTLY! You want just enough binder to hold the crab together, not to break it apart. Season lightly with salt and pepper, tasting a tiny bit if you're comfortable (or just trust the Old Bay!).
Once the mixture is just combined and looks moist enough to hold its shape, it's time to form your bombs! Scoop out rounded tablespoons or golf-ball sized portions of the mixture. Gently roll or press them into compact balls. Don't pack them too tightly, you want them to stay tender. Place them on your prepared baking sheet.
Melt the 2 tablespoons of butter in a small dish. Use a brush or a spoon to drizzle a little bit of melted butter over the top of each crab bomb.
Pop the baking sheet into your preheated oven. Bake for 15-18 minutes, or until the crab bombs are heated through and the tops are lightly golden brown and slightly firm.
Carefully remove them from the oven. If desired, give them a final sprinkle of additional Old Bay seasoning. Serve them warm and watch them disappear!