Step 1

Make the cake: Preheat the oven to 350°F. Butter a 9-inch springform pan, line the bottom with a circle of parchment paper, and set aside.

Step 2

In a large bowl, stir together the almond flour, shredded coconut, cinnamon, and salt.

Step 3

In the bowl of a stand mixer fitted with the paddle attachment, beat together the sugar and lemon zest on medium-low until fragrant, about 1 minute. Add the softened butter and keep beating, pausing to scrape down the bottom and sides of the bowl and the paddle as needed, until the mixture is pale and fluffy, 4–5 minutes. Add the egg yolks and continue beating until velvety and smooth, 3–4 minutes. Add the almond extract and orange blossom water, then turn the mixer down to low and add the reserved almond flour mixture gradually, pausing to scrape down the bottom and sides of the bowl as needed, until fully incorporated. Remove the bowl from the mixer and set aside.

Step 4

In a clean medium bowl, whisk the egg whites to glossy soft peaks, about 3 minutes. Using a spatula, gently fold the whites into the cake batter in 3 batches until fully incorporated. Pour the batter into the prepared springform pan, sprinkle evenly with sliced almonds, and bake until a cake tester inserted in the center comes out mostly clean, with a few crumbs, 60–70 minutes. Let cool in the pan for 30 minutes, then remove, slide onto a wire rack, and continue cooling at least 30 minutes more.

Step 5

In a small bowl, stir together the confectioners sugar and cinnamon. When the cake has fully cooled, dust the top surface with cinnamon sugar. Cut into slices and serve at room temperature. Leftover almond cake can be stored at room temperature in an airtight container for up to three days.