Romaine Salad with Red Onions, Walnuts and Orange Vinaigrette

1 cup walnut pieces

1 sack pre-washed chopped romaine or 2 hearts, chopped, about 6 cups

1/2 red onion, finely chopped

1 tablespoon orange marmalade

1/4 teaspoon crushed red pepper flakes

1 small sprig rosemary, stripped and finely chopped or 1/2 teaspoon dried, crushed

2 tablespoons balsamic vinegar

1/4 cup extra-virgin olive oil, eyeball it

Salt