Preheat oven to 350F. Place 10 parchment muffin liners into a 12-cup muffin tin; set aside.
For the pineapple layer: Measure one heaping cup of fine diced pineapple. Use a small lid placed over the measuring cup to press the pineapple down in the cup in order to squeeze the pineapple and extract the juices. Pour out the juice (or reserve for another use). Set pressed pineapple aside.
In a medium bowl, whisk together the melted butter (or coconut oil), coconut sugar and vanilla until well combined. Add the pineapple and stir well to combine.
Evenly divide the pineapple mixture along the bottom of the 10 muffin cups. Set muffin tin aside.
For the muffins: In a small bowl, combine the almond flour, coconut flour, baking soda and salt. In a large bowl, whisk together the eggs, yogurt, honey, lemon juice and vanilla until well blended. Using a spoon, stir the dry ingredients into the wet and mix until well blended.
Spoon the muffin batter over the top of the pineapple layer, making sure to evenly divide the batter among each of the 10 muffin cups.
Bake for approximately 15-20 minutes, until a toothpick inserted into the center comes out clean. Allow muffins to cool in the tin for five minutes. Then transfer to a wire rack to finish cooling.
Then, gently remove the paper liners from each muffin and place on a serving plate with the pineapple layer facing up. Enjoy!