Bring a pot of water to a boil; cook fiddlehead ferns in the boiling water until tender, about 5 minutes. Drain.
Heat a 9-inch cast iron skillet over medium-high heat. Cook and stir lamb in the hot skillet until browned and crumbly, 5 to 7 minutes. Add chard, carrot, celery, onion, and peas; cook, stirring occasionally, until chard is wilted and vegetables are softened, about 10 minutes.
Mix lamb stock, quinoa, and curry powder into lamb mixture; cover and bring to a boil. Reduce heat to low and simmer until quinoa is tender and most liquid is absorbed, about 15 minutes.
Remove skillet from heat and stir fiddlehead ferns and garlic into quinoa-lamb mixture; season with salt and pepper. Let sit for 5 minutes before serving.