Position a rack in the lower third of the oven and preheat to 325ºF. Butter a solid 10-inch round tart pan with 1.25-inch high sides or a 9-inch round cake or spring form pan (if using a cake pan, line the bottom with a round of parchment cut to fit). Dust the pan with flour and tap out the excess, and place on a baking sheet to catch any drips.
In the bowl of a stand mixer fitted with the paddle attachment, beat the almond paste and butter until combined, scraping down the bowl and beater as needed.
Add the sugar, and beat on medium until light and fluffy, 3 minutes.
Add the eggs one at a time, beating until combined after each addition, then add the almond and vanilla extracts. It’s fine if the mixture looks broken at this point.
Sift the oat flour, almond flour, baking powder and salt into a medium bowl, and add to the cake batter, beating until well-combined. Increase the mixer to medium and beat until fluffy, 10 seconds.
Scrape down the bowl and beater, give the batter a final fold with a spatula to make sure it is homogeneous, then spread into the pan.
Place the raspberries evenly on top of the cake, decorate the edges with the almonds, and sprinkle with the coarse sugar.
Bake the cake until the top is golden and a tester inserted near the center comes out with a few moist crumbs, 40-50 minutes. Let the cake cool completely, about 1 hour.
When ready to serve, combine the cream, sugar, and vanilla paste in the bowl of a stand mixer fitted with the whisk attachment and whip until soft peaks form. Chill until needed.
To serve, dust the cake lightly with powdered sugar, cut into wedges, and serve with vanilla bean whipped cream. Note: the cake keeps well for up to 1 day at room temperature or up to several days refrigerated airtight.
