Preheat oven to 350 F.
In the bowl of a stand mixer, mix ground almonds, flour, sugar, and lemon zest until combined.
Add the softened butter and beat for 2 minutes. Scrape down the bowl.
Add the vanilla. Add the egg whites, one by one, beating for 2 minutes and scraping down the bowl after each addition.
Divide the batter evenly between the prepared molds. Place on raspberries and sprinkle with sliced almonds.
Bake until golden brown, about 30 minutes, but depending on the mold/pan used.
Unmold the cakes, let cool on a cooling rack.
Sprinkle with powdered sugar and serve.
Financiers are the very best when eaten on the day they are baked.