Preheat oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners.
In a medium bowl, combine the almond flour, sugar, and softened butter. Beat in the egg and almond extract until smooth. Set aside.
½ cup almond flour, ½ cup granulated sugar, ¼ cup unsalted butter, 1 egg, ½ teaspoon almond extract
In a large bowl, mix together the softened butter, sugar, almond extract, vanilla extract, egg, sour cream and milk.
½ cup butter, ¾ cup granulated sugar, 1 egg, ½ cup sour cream, ½ cup milk, 1 teaspoon almond extract, ½ teaspoon vanilla extract
In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.
2 cups all-purpose flour, 1 ½ teaspoons baking powder, ½ teaspoon baking soda, ¼ teaspoon salt
Gradually add the dry ingredients to the wet ingredients. Mix lightly, scraping the sides of the bowl, until just combined.
Spoon about 2 tablespoons of muffin batter into each muffin liner.
Top each with about 1 tablespoon of the frangipane filling.
Spoon another 1-2 tablespoons of muffin batter over the frangipane, gently spreading to cover.
Sprinkle slivered almonds over the top of each muffin.
¼ cup slivered almonds
Bake for 20-23 minutes, or until a toothpick inserted into the center comes out clean and the tops are golden brown.
Let the muffins cool in the muffin tin for a few minutes before transferring them to a wire rack to cool completely.