Preheat the oven to 375 degrees. Grease and set a 9-inch tart pan. If you have a pan with a removable bottom, you may want to place it on a baking sheet for easier handling.
To make the crust: In a large bowl, whisk together the flour and powdered sugar. Add the butter in small chunks and mix with a paddle attachment on medium until uniform crumbs form. Place the dough into the tart pan, and firmly and evenly press into shape.
To make the filling: In a medium bowl, whisk together sour cream, heavy cream, egg, sugar, and almond extract until well combined.
Pour the tart filling into the prepared crust and evenly distribute fresh blueberries over the filling, pressing down slightly so that they are mostly submerged.
Bake in the preheated oven until the filling has set and the crust is golden, about 25 minutes. When you take the crust out of the oven, the center of the crust should wobble ever-so-slightly, while the outsides remain set. Cool on a wire rack. Serve warm, or chilled from the refrigerator.