1. Preheat oven to 400 degrees F. Place rack in center of oven. If you are making 12 muffins, lower the oven temperature to 375 F.

2. Prepare your muffin pan with non-stick cooking spray, butter, or paper liners. Set aside.

3. Whisk flour, baking powder, salt, and cinnamon in a medium bowl until combined.

4. In a large bowl, whisk eggs, then add sugar. Whisk until pale in color, then add oil and vanilla extract.

5. Gradually add dry ingredients to wet. Stir gently with a wooden spoon until just a little flour shows. Do not overmix.

6. Gently fold in apples, cranberries, and walnuts if using.

7. Spoon batter into prepared muffin cups. Sprinkle tops with granulated sugar if using. Bake for 25 to 30 minutes for regular size muffins, or 40 minutes for 6 large muffins, until golden brown and a toothpick in the center comes out clean.

8. Cool in pan for a few minutes, then turn out onto wire racks.