1.Bring a large pot of water to a boil with 1 teaspoon salt. Cook pasta according to package directions but just shy of al dente.
2.Meanwhile, in a medium saucepan over medium heat, melt butter. Whisk in flour until it forms a paste (roux). Cook for 3 - 4 minutes. Add white wine while whisking constantly. Then add broth, while whisking.
3.Add garlic, salt and pepper. Stir to combine and bring to a simmer. Add langostinos, cook for 1 - 2 minutes to warm langostino. Remove from heat and add chopped parsley and lemon juice. Add pasta and combine, if the pasta is dry add a bit of pasta water to loosen.