Wash kale if needed, and spin dry or dry with paper towels.
Heat the oil in a large frying pan on medium-high. When the oil is hot, add the kale and saute until it's softened into a flat layer, about 3min.
Spray slow cooker well with non-stick spray or oil and transfer the cooked kale to the slow cooker.
Drain red peppers and chop into fairly small pieces. Slice the green onions and crumble the Feta. Add the chopped red pepper and sliced green onion to the slow cooker with the kale.
Beat the eggs well, pour over other ingredients in the slow cooker, and stir so all ingredients are well-combined. Season with all purpose seasoning and black pepper, then sprinkle on the crumbled pressed cottage cheese.
Cook on low for 2 - 3 hours, or until the frittata is well set.