Preheat the oven to 350℉. Coat a 9x9 square baking pan with avocado or coconut oil spray and place a parchment sling into the pan for easy removal. Set aside.
In a medium bowl, sift together the almond flour, tapioca flour, cacao powder, and salt. Set aside.
In a large mixing bowl, or a stand mixer fitted with the whisk attachment, add the eggs. Beat on medium-high for 3 to 4 minutes until they are pale yellow and fluffy. Mix in the avocado oil, maple syrup, coconut sugar, coconut milk, vanilla extract, vinegar, and baking soda. Beat on medium to combine.
Adjust the mixer speed to medium-low, and working in increments, slowly add the dry ingredients to the wet ingredients, scraping the sides of the bowl as needed. Mix for 1 to 2 minutes until everything is well combined. Add the red food gel and mix once more.
Tip the batter into the prepared baking pan. Transfer to the oven and bake until the top is lightly browned and when pricked with a cake tester it comes out clean, about 25 minutes. If the top starts to get overly browned, place a sheet of foil over the top, but do note this is a darker cake.
Remove from the oven and allow the cake to cool in the pan for 10 minutes. Then use the parchment sling to carefully transfer the cake to a wire rack until completely cooled before you frost..