Heat 1/4 cup of oil in a pot. Add half the garlic, cook for 1 minute, then add clams. Pour in the wine, cover, and cook for 5-7 minutes. Transfer opened clams to a baking sheet and strain liquid into a blender with roasted peppers; puree until smooth.

Clean the pot, heat remaining oil, add garlic, and cook for 1 minute. Add crushed red pepper and Swiss chard in batches until wilted, about 3 minutes. Stir in pepper broth; season with salt and pepper.

Cook spaghetti until al dente in boiling salted water; drain. Combine spaghetti with Swiss chard mixture, butter, lemon zest, lemon juice, and cheese. Add clams and toss. Serve in bowls, garnished with more cheese.