Preheat the oven to 325 F (163 C). Grease and line the bottom of a 9-inch (23 cm) springform or cake pan with parchment paper. Move the center rack from the center of the oven to the level right below (lower third of the oven). In a large bowl, whisk together the flour, almond flour, baking powder, baking soda and salt together until well combined.
1¾ cups (210 g) all purpose flour, ½ cup (48 g) almond flour, 2 teaspoon baking powder, ¼ teaspoon baking soda
In a large mixing bowl fitted with paddle attachment, beat the sugar and lemon zest together until they are the consistency of wet sand. Beat butter and lemon sugar together until light and fluffy. This takes about 2-3 minutes on medium speed.
1 cup (200 g) granulated sugar, 1 lemon, zested, ½ cup (113 g) unsalted butter, room temperature
On low, beat in the eggs, almond extract and vanilla extract until smooth and well combined.
2 teaspoon (10 ml) almond extract, 1 teaspoon vanilla extract, 2 large eggs (US), room temperature
Alternating dry ingredients and sour cream, mix in ⅓ of the dry ingredients into the wet, followed by ½ of the sour cream. Repeat until all the ingredients are just combined.
1 cup (240 g) sour cream, room temperature
Evenly spread the almond cake batter into the prepared pan. Top with the sliced almonds.
¼ - ½ cup (30 - 60 g) sliced almonds for topping
Bake the almond flour cake for 35-45 minutes or until a toothpick inserted into the center of the almond cake comes out clean or with a few moist crumbs.
Cool the cake in the pan for 15-20 minutes. Gently release the side of the springform pan and allow the cake to cool for 5-10 more minutes. Transfer the lemon almond cake to a serving plate or serve right from the pan. Top with powdered sugar, slice and enjoy! 2 tablespoon (15 g) powdered sugar for topping