• Position racks in the oven and preheat to 350°F (175°C). Grease two 8-inch cake pans, line the bottoms with parchment rounds, and set aside.

For the Cake:

• Reserve 1/4 cup of the all-purpose flour; whisk the remaining all-purpose flour with the almond flour, baking powder, salt, cardamom, and cinnamon in a large bowl until evenly combined.
• In a stand mixer fitted with the paddle, beat the room-temperature butter and granulated sugar on medium speed until pale and airy, about 4–6 minutes.
• Lower the mixer speed and add the eggs one at a time, mixing briefly after each addition until incorporated.
• Reduce speed to low and add the dry mixture and buttermilk in three alternating additions, beginning and ending with the dry ingredients. Stir in the vanilla and almond extracts until just combined.
• Toss the reserved 1/4 cup flour with 1/4 of the blueberries to coat them; gently fold the floured berries into the batter to help prevent color bleeding.
• Divide the batter evenly between the prepared pans. Scatter the remaining reserved blueberries on top of each cake for a pretty finish.
• Bake until a toothpick inserted into the center comes out clean, about 35 minutes. Let cakes cool in the pans for 10–15 minutes, then turn them out onto a wire rack to cool completely.

For the Pistachio Cream:

• In the mixer bowl fitted with the paddle, beat the butter and salt on medium-high for about 1 minute until slightly lightened.
• Add the crema al pistacchio and mix until combined, about 1 minute more.
• With the mixer on low, gradually add the powdered sugar to avoid dust; once incorporated, raise the speed to medium-high and beat until the mixture lightens, about 2 minutes.
• Swap to the whisk attachment and continue beating until the cream becomes fluffy and airy, roughly 6–8 minutes. Add vanilla bean paste and the 2 tablespoons of buttermilk as needed to reach a spreadable, smooth consistency.

Assembly:

• Place one cooled cake layer on a serving plate and spread a generous layer of pistachio cream over the top, smoothing toward the edges while leaving a shallow well in the center.
• Set the second cake layer on top, cover with the remaining pistachio cream; shape it into a large dollop and create a small bowl at the top to hold the fresh blueberries.
• Fill the center well with the reserved fresh blueberries and garnish with edible flowers if using. Chill in an airtight container; the cake keeps up to one week refrigerated but is best within two days.