Add butter to a pan, then add the chopped chards, salt, pepper, and cook. Take the roasted chards to a large plate and let them cool. In a deep bowl, mix the eggs, flour, baking powder, milk, Tat Walnut Paste, and basil with a mixer. Add the roasted chards and grated feta cheese, stir it with a spoon. Oil the pan with sunflower oil and let it heat. Pour the pancake mix to the pan and cook both sides well like an omelette. Serve the pancakes hot.