Preheat the oven to 350°F. Brush the bottom of a 9-inch springform pan with softened butter. If you don't have a springform pan, you can brush the bottom of a 9-inch round pan with butter and line it with a round of parchment paper. Without a springform pan, if you opt for the nuts and strawberries on top, you'll need to serve the cake out of the pan.

In a medium bowl, sift together almond flour, oat flour, baking powder, baking soda, and salt. Set aside.

Using a hand mixer, whisk the egg whites in a medium bowl, starting on low speed and increasing to high speed until soft peak form. When the beater is pulled out a peak should rise and the very tip should fall. Set aside. Alternatively, use a stand mixer fitted with the whisk attachment. Once whipped, transfer the egg whites to a clean bowl while you prepare the rest of the cake. Wipe the bowl out quickly with a paper towel.

In the bowl of a stand mixer fitted with the paddle attachment or a large mixing bowl with a hand mixer, cream the butter and sugar together until light and fluffy, 2-3 minutes, scraping down the sides as needed.

Add the lemon zest and beat until evenly distributed.

Add the eggs yolks mixing until combined and scraping down the sides after each addition. Beat in the vanilla and almond extracts until just combined.

With the mixer on low, add the dry ingredients in two additions, alternating with the milk, scraping down the sides after each addition and mixing until just combined.

Mix in ⅓ of the whipped egg whites to loosen the batter. Using a silicone spatula, fold in the remaining egg whites until just combined.

Bake on the middle rack for 45-50 minutes, until a toothpick inserted into the center comes out clean or with just a few crumbs.