Preheat the oven to 350°F (180°C). Grease an 8-inch round cake pan with non-stick oil spray and line it with parchment paper. Lightly grease the parchment paper as well.
Whisk flour, almond flour, baking powder, baking soda, and salt in a medium mixing bowl. Set aside.
Combine the olive oil, sour cream, sugar, lemon juice, zest, and vanilla in a large mixing bowl. Whisk until well combined.
Add the flour mixture and milk to the wet mixture in two parts. Mix until everything is just combined. Do not overmix.
Pour it into the prepared pan, spread it evenly, and smooth the top.
Bake the cake for 28-32 minutes or until a cake tester inserted in the center comes out clean.
The baking time may vary, more or less, depending on the oven, so keep an eye on the oven while baking.
Remove the cake from the oven, place the pan on the cooling rack, and let the cake cool completely in the pan.
Once the cake is cooled, remove it from the pan and sprinkle icing sugar on top, if you prefer, before slicing and serving.