Preheat the oven to 350°F (177°C).

Grease a 9-inch springform pan and lightly dust it with flour. Set aside.

In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt.

In a separate large mixing bowl, beat the softened butter and granulated sugar on high speed for about 2 minutes, until creamy and smooth.

Scrape down the sides and bottom of the bowl as necessary.

Add the eggs, sour cream, vanilla extract, and almond extract.

Beat on medium-high speed until combined. The mixture may appear slightly curdled at this stage, which is normal.

Add the dry ingredients and mix on low speed just until a thick, smooth batter forms. Avoid overmixing.

Spread the batter evenly into the prepared springform pan.

To prepare the crumb topping, combine the flour, brown sugar, and cinnamon in a small bowl.

Stir in the melted butter with a fork until small crumbs form.

Distribute the raspberries evenly over the cake batter. If using frozen raspberries, add them directly from the freezer without thawing.

Sprinkle the crumb mixture evenly over the berries.

Finish with the sliced almonds.

Bake the Raspberry Almond Crumb Cake for 35–40 minutes, or until a toothpick inserted near the center comes out clean.

If the almonds or top of the cake begin browning too quickly, loosely tent the pan with aluminum foil for the remaining baking time.

Remove the cake from the oven and place the pan on a wire cooling rack.

Let the cake cool slightly before carefully removing the outer ring of the springform pan.

Dust with confectioners' sugar, if desired, then slice and serve.