Preparation

• Bring a large pot of salted water to a boil.
• Meanwhile, heat the oil, butter, garlic, red pepper flakes, and a pinch of salt in a deep 12-inch skillet over low heat, stirring once or twice, until the garlic begins to gently sizzle, about 3 minutes. Cook, stirring occasionally, until the garlic is soft (you don’t want it to color), 3 to 4 minutes.
• Add the crabs belly side down, cover, and slowly cook, shaking the pan occasionally so the crabs don’t stick, until they are red and an instant-read thermometer inserted in the center reads about 145°F, about 10 minutes.
• When the crabs go into the skillet, begin cooking the spaghetti until just shy of al dente. During the last minute of cooking, add the spinach and peas to the pasta water to heat through and wilt. Reserve 3/4 cup of the cooking water; drain the pasta and vegetables.
• When the crabs are done, turn the heat off, hold each crab above the skillet with tongs and cut it into bite-size pieces with poultry shears, letting the pieces fall back into the skillet.
• Add the pasta and vegetables to the skillet along with the parsley, and gently toss over medium heat until the spaghetti is al dente and well coated with the sauce. Add some of the reserved water if it looks dry. Season to taste with salt and pepper. Serve drizzled with olive oil and sprinkled with the chives.