In a food processor, pulse the onion and garlic until minced. Melt the butter in a medium saucepan. Add the onion and garlic and cook over moderate heat until softened, about 7 minutes. Add the cinnamon, ginger and cayenne and cook, stirring, for 2 minutes. Stir in the tomato sauce and honey and simmer over low heat until the sauce thickens slightly, about 5 minutes. Season with salt and pepper.