Spaghetti with Mussels and White Beans

Heat butter and 2 tablespoons oil in a large heavy pot over medium-low heat. Add garlic and red pepper flakes and cook, stirring often, until beginning to brown, about 2 minutes. Add tomatoes with juices, crushing tomatoes lightly with your hands. Increase heat to medium-high. Cook, stirring often, until sauce thickens, 10-15 minutes. Meanwhile, cook pasta in a large pot of boiling salted water, stirring occasionally, until al dente. Drain pasta, reserving 1 1/2 cups pasta cooking liquid. Add beans and wine to sauce. Cook, stirring often, until wine has almost evaporated, about 4 minutes. Add mussels and 1/4 cup pasta cooking liquid. Cover; cook, stirring occasionally, until mussels open, about 4 minutes (discard any that do not open). Add pasta and 1/4 cup pasta cooking liquid to mussels and stir to coat. Reduce heat to medium and continue stirring, adding more cooking liquid as needed, until sauce coats pasta. Divide among bowls. Drizzle with oil; garnish with parsley.