In the bowl of a stand mixer fitted with the paddle attachment, beat granulated sugar, sour cream, heavy cream, melted butter and vanilla extract at medium speed until well combined, about 2 minutes, stopping to scrape sides of bowl.
In a large bowl, whisk together flours, poppy seeds, baking powder, and salt. Add flour mixture to sugar mixture, just until combined. Fold in strawberries.
Line bottom of pan with parchment paper.
Spoon batter into prepared pan; spread into an even layer. Sprinkle with sliced almonds.
Bake for 60 minutes.Bake until a wooden pick inserted in center comes out clean. Let cool in pan on a wire rack for 10 minutes. Carefully remove sides of pan; let cake cool completely on bottom of pan on a wire rack.
Before serving, garnish with confectioners’ sugar.