Preheat the oven to 350°F Spray one mini muffin pan with a light coating of cooking oil spray. You can also use individual ramekin baking cups, but the yield will be less.
In a large bowl, combine the 4 egg yolks, agave syrup, vanilla, baking soda, and salt in a large bowl. Using an electric mixer, beat until the ingredients are well blended.
Add the almond flour or meal and beat on low speed until combined, about 2 minutes.
Place the 4 egg whites in a large, clean bowl. Use either a handheld mixer with clean beaters or the whisk attachment on a stand mixer and beat the whites on medium speed until opaque, doubled in volume with soft peaks.
Using a rubber spatula, gently fold the egg whites into the batter until just combined. Scrape the batter evenly into the prepared muffin cups, filling each three-quarters full. Bake, rotating halfway through, until the edges are light brown and a dime-sized soft center remains, 18 to 20 minutes. If using larger baking cups, you’ll need to increase the baking time by 5 to 10 minutes. Transfer the pan to a wire rack and let cool completely, at least 15 minutes.
To make the berry topping, combine all the ingredients in a large microwaveable bowl and toss until combined. Microwave on high for 2 minutes, then stir and microwave again until slightly thickened and steaming, about 2 1/2; minutes more.
Unmold the cakes. To serve, spoon 1 tablespoon of the warm berry topping on each cake. Extra cakes may be stored in an airtight container at room temperature for up to 7 days.