Tortilla Black Bean Pie

I originally got this recipe from my sister who saw it in an issue of Martha Stewart's Everyday Food magazine. It's simple and has fed our family on occasion when there wasn't too much in the cupboard. It's also a great vegetarian dish.

• 4 (10-inch) flour tortillas (I have used smaller and just overlapped them to fit the pan)
• 1 tablespoon canola oil
• 1 large onion, diced
• 2 cloves garlic, minced
• 1/2 teaspoon ground cumin
• Coarse salt and ground pepper
• 2 cans (15 ounces each) black beans, drained and rinsed
• 1 1/2 cups water
• 1 package (10 ounces) frozen corn (I often use canned)
• 4 green onions, thinly sliced, plus more for garnish
• 2 1/2 cups (8 ounces) shredded cheddar cheese (I usually use sharp but that's just me)

Preheat oven to 400 degrees. Trim tortillas to fit a 9-inch springform pan, using the bottom of the pan as a guide. Set aside.
Heat oil in skillet over medium heat. Add onion, garlic, and cumin; Cook, stirring occasionally, until onion is softened, 5 to 7 minutes.
Add beans and water to skillet, and bring to a boil. Reduce heat to medium; simmer until liquid has almost evaporated, 8 to 10 minutes. Stir in corn and green onions, and remove from heat. Add salt and pepper to taste.
Fit a trimmed tortilla in bottom of springform pan; layer with 1/4 of the beans and 1/2 cup cheese. Repeat three times, using 1 cup cheese on top layer. Bake until hot and cheese is melted, 20 to 25 minutes. Unmold pie; sprinkle with additional green onions. To serve, slice into wedges. 

We often eat ours with sour cream and salsa. Esmiley had left a  comment on the original post that she has a guacamole and salsa variation. Sounds fantastic! 
(Recipe and photo taken from marthastewart.com with minor modifications)