Once, when we arrived at a friend’s barbecue, we were disappointed to learn we’d be eating pizza. Then, out on the back deck, we spied this big, green, egg-shaped thing. “What’s that?” we asked. “That’s my BIG GREEN EGG,” our friend said. “I’m cooking the pizza in it.” Cooking pizza in a grill? One taste, though, and we were hooked. It turns out the egg — based on the ancient Chinese cooker called a “kamado” — was invented in Tucker, now the worldwide headquarters of the Big Green Egg. The ceramic egg, which starts at $359, can act as a grill or smoker. Our favorite part of the cookout? When our host pulled out the apple pie; he had cooked it — you guessed it — in the egg.