Preheat the oven to 400 F (200 C).
Line a 12-cup muffin tin with paper liners. Set aside.
In a bowl, combine the flour, baking powder, salt, sugar, and almond powder.
Add the cranberries and mix gently until the fruit is just coated.
In another bowl, mix the buttermilk, eggs, almond extract, and melted butter until the mixture is well combined.
Pour the wet ingredients into the dry ingredients and mix gently until no dry ingredients are visible.
Divide the batter among the prepared muffin cups.
The batter will fill the cups but will not overflow during baking.
Sprinkle the tops of the muffins with sliced almonds, then sprinkle with brown sugar or turbinado sugar.
Bake on the middle rack for 20 minutes or until a toothpick inserted into the center of a muffin comes out clean.
Remove from the oven and let rest for 5 minutes before transferring to a cooling rack.