Preheat oven to 425°F (220°C) and line a standard 12-cup muffin pan.
Whisk together the all-purpose flour, almond flour, baking powder, baking soda, and salt.
In a separate large bowl, whisk together the melted butter and sugar. Add the eggs and whisk until combined.
Add the Greek yogurt, milk, vanilla extract, and almond extract and whisk until incorporated.
Fold the dry ingredients into the wet ingredients just until combined.
Reserve about 12 frozen raspberries. Gently fold the remaining frozen raspberries into the batter.
Divide the batter evenly among the 12 muffin cups. Press one reserved raspberry into each muffin and add sliced almonds, if desired.
Bake at 425°F for 5 minutes. Without opening the oven, reduce the temperature to 350°F (175°C) and bake for another 15–19 minutes, or until a toothpick inserted away from a raspberry comes out clean or with a few moist crumbs.
Cool in the pan for 5–10 minutes before transferring to a wire rack.