Preheat your oven to 180°C (350°F) and line a muffin tin with paper liners or lightly grease the cups.
In a large bowl, whisk together the cottage cheese, eggs, and softened butter until smooth and well combined.
In another bowl, sift together the flour, sugar, baking powder, and salt.
Gradually add the dry ingredients into the wet ingredients, stirring until just incorporated. Be careful not to overmix.
Gently fold in the chopped apples, and add optional nuts or raisins if desired.
Spoon the batter into the muffin cups, filling each about 2/3 full.
Bake for 20-25 minutes, or until the muffins are golden brown and a toothpick inserted into the center comes out clean.
Allow the muffins to cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.