1) Melt the butter in a saucepan over medium heat. Add the onion, garlic, jalapeno, and salt and season with pepper to taste. Cook, covered, stirring occasionally, until soft, about 5 minutes. Add the corn and sugar and cook, covered, stirring occasionally, until soft, about 10 minutes. (If the mixture gets dry while cooking add a couple tsp water.)
2) Raise the heat to medium-high, add the butter beans and marjoram and cook, stirring, for 3 minutes. Stir in the tomatoes and parsley and season generously with pepper. Serve immediately.