Preheat your oven to 350°F. Line the bottom of an 8-inch or 9-inch springform pan ( I used a 9 inch one) with parchment paper and grease the sides or grease the entire pan. Wash the blackberries and dry them completely with paper towels. This helps prevent extra moisture in the cake.

In a large bowl, whisk together the eggs, coconut sugar, melted coconut oil, applesauce, sour cream, vanilla, lemon zest, and lemon juice until smooth.

Next, add the almond flour, tapioca flour (arrowroot starch can be used as a 1:1 substitute. Cornstarch should also work, though the texture may be slightly softer), baking soda, baking powder, and salt. Stir until just mixed and a thick batter forms. Be careful not to overmix as that can result in a dense cake.

Add the blackberries to a small bowl and toss with 1–2 tablespoons tapioca flour. Add the blackberries to a small bowl and toss with 1–2 tablespoons tapioca flour (arrowroot and cornstarch can be used as a 1:1 substitute for coating the berries). This helps prevent the berries from sinking and keeps the cake from becoming too wet. Fold the blackberries gently into the batter. Spread the batter into the prepared pan and smooth the top.

Bake for 50–60 minutes, or until the top is golden, the center looks set, and a toothpick comes out mostly clean. Because almond flour cakes stay softer, a few moist crumbs are okay.

Let the cake cool for at least 20–30 minutes before slicing. This helps the almond flour cake fully set and slice more cleanly. Remove from pan by releasing the latch on the side of the pan and gently expanding the collar so it pulls away from the cake. Lift the metal ring straight up to remove it and take out the cake. If using a parchment paper circle, you can carefully slide it off the bottom of the pan. If not, use a cake lifter or large offset spatula to transfer it to a serving platter.