Meat ragù traditionally requires a long simmer over low heat, but this 45-minute version owes its slow-cooked flavor to a hefty dose of red-pepper or chile paste, which yields a complex, hearty sauce. (This recipe calls for sambal oelek, which is easy to find, but Calabrian chile or Hungarian paprika paste would work well, too.) Spoon the ragù over cooked, broken lasagna noodles and top it with a dollop of creamy ricotta, a sprinkle of toasted fennel and a few curls of lemon zest. This…