Preheat your oven to 400°F (200°C). This ensures that your scones will bake evenly and become golden brown.
Line a baking sheet with parchment paper to prevent sticking and make cleanup easier.
In a large mixing bowl, whisk together the all-purpose flour, baking powder, granulated sugar, and salt until well combined.
Add the cold, cubed butter to the flour mixture. Using a pastry cutter or fork, cut the butter into the flour until the mixture resembles coarse crumbs with small pea-sized pieces of butter.
In a separate bowl, mix together 1 cup of heavy cream with the almond extract for moisture and flavor.
Pour the wet mixture into the dry ingredients, stirring gently until just combined. A few lumps are okay; avoid overmixing.
Gently fold in the raspberries and sliced almonds, being careful not to break the raspberries too much.
Turn the dough out onto a floured surface. Pat it into a 1-inch thick circle. Slice into 8 wedges using a sharp knife or pizza cutter.
Carefully transfer the scones to the prepared baking sheet, spacing them apart.
Mix the remaining tablespoon of heavy cream and brush it over the tops of the scones for a golden color.
Bake the scones for 18-20 minutes, until lightly golden on top.
While baking, prepare the almond glaze by whisking powdered sugar, 4-5 tablespoons of heavy cream or milk, and 1/2 teaspoon almond extract until smooth and pourable.
Once baked, cool the scones on a wire rack for a few minutes. Drizzle the almond glaze over the warm scones and sprinkle with sliced almonds for garnish.