Preheat oven to 400°F. Prepare a loaf pan by buttering the short sides. Drape a sheet of parchment paper (cut to fit) into the pan, leaving an inch overhang on each of the long sides.
Heat olive oil in small frying pan then add onion and cook until softened, about 5 minutes.
Crack eggs into a medium sized bowl and whisk together with cream. Add quinoa, black beans, chiles, diced red pepper, cilantro or parsley and seasonings. Stir gently to combine and pour into prepared pan. Bake 25 - 30 minutes, until top has a golden crust and a knife inserted into the middle comes out clean. Let cool 10 minutes, then remove from pan by lifting by the parchment. Cut in inch-thick slices and serve warm or at room temperature with lettuce, cilantro, avocado, sour cream, and wedges of lemon or lime.