Heat the oven to 375°F with a rack in the middle position. Mist a 9-by-13-inch baking pan with cooking spray, dust evenly with flour, then tap out the excess.

In a food processor, combine the flour, white sugar, baking powder, cinnamon and salt. Pulse until well combined, 6 to 8 pulses.

Scatter the 12 tablespoons butter over the dry ingredients and pulse until the mixture resembles coarse crumbs, about 20 pulses. Transfer to a large bowl, then measure out 165 grams (1 cup) of the mixture and return it to the food processor.

To the food processor, add the brown sugar, almonds and remaining 2 tablespoons butter, then pulse until the mixture begins to clump and resembles wet sand, about 20 pulses; transfer to a medium bowl and set aside.

In another medium bowl, whisk together the eggs, sour cream and vanilla. Pour into the large bowl of flour-butter mixture and fold with a silicone spatula until only a few streaks of flour remain.

Add the cranberries and candied ginger, then fold until evenly distributed; the batter will be thick. Transfer to the prepared pan and spread in an even layer.

Using your hands, squeeze the almond-flour mixture into rough ½-inch clumps, then scatter evenly over the batter in the pan. Bake until the topping is golden brown and a toothpick inserted at the center comes out clean, 40 to 45 minutes.

Cool in the pan on a wire rack for at least 30 minutes before slicing. Dust with powdered sugar just before serving, if desired.