Preheat oven 350 F. Prepare a muffing tin with muffin liners or cooking spray.
In a medium bowl, mix together the dry ingredients until broken down and incorporated well.
In a separate large bowl, whisk together egg whites, honey and oil.
Fold the dry ingredients into the wet ingredients and stir just until combined. Do NOT over stir. Coconut flour is very absorbent so you want to gently fold the ingredients together. Gently fold in the chopped apples.
Scoop the batter into the muffin cavities filling 3/4 of the way full. I used my finger to smooth the edges so the muffins would puff nicely.
Bake 22-25 minutes until muffins are golden brown. Remove from the oven and transfer to a wire baking rack to cool 5-10 minutes before removing and enjoying.
Notes
Measure the flours by spooning them into the measuring cup rather than scooping them directly and packing in the flour. Too much flour will dry out the muffins.
The batter should be thick and scoopable, not drippy. This will help hold the apples in place to avoid them sinking to the bottom of the muffins.
Use your finger to smooth along the edge of the muffin cups. This will help create a round dome at the top of the muffins.