Preheat oven to 350°F. Line a muffin tin with paper liners or spray lightly with cooking spray.
Mix dry ingredients: In a large bowl, whisk together almond flour, oats, cinnamon, baking soda, and salt.
Mix wet ingredients: In another bowl, beat eggs, maple syrup (or honey), oil, and vanilla until smooth.
Combine: Add wet ingredients to dry and stir until just combined. Fold in canned apples and walnuts.
Fill muffin tins: Spoon batter evenly into muffin cups. Optionally sprinkle with a little cinnamon sugar or extra chopped walnuts.
Bake: Bake for 20–25 minutes, or until a toothpick inserted in the center comes out clean.