Vegetarian Tamales

2 to 3 tablespoons canola or vegetable oil
1/2 cup onion, minced
1 teaspoon garlic, minced
3/4 cup frozen edamame, thawed, shelled (whole green soybeans)
3/4 cup frozen corn, thawed
2/3 cup zucchini, grated
1/4 cup red bell pepper, finely chopped, roasted, from a jar
Salt and black pepper, freshly ground, to taste
1/2 teaspoon oregano
1 teaspoon parsley, dried
1/4 teaspoon New Mexico chili powder, dried, or more, to taste
1/2 teaspoon ground cumin, or more, to taste
Masa Harina, mixed according to package directions,
    enough for about 2 dozen tamales
1 package dry corn husks, soaked in hot water for about 10-15 minutes

Filling: In a nonstick skillet or saut