Line an 8×8 inch baking tin with parchment paper and grease the sides with melted butter. Preheat your oven to 350°F (170°C).
In a medium mixing bowl, whisk together all the dry ingredients until well combined. Set aside.
In a large mixing bowl, add the butter, cream cheese, and granulated stevia. Cream using a hand mixer for 2-3 minutes until creamy, smooth, and slightly fluffy.
Add the eggs, vanilla, and almond extract if using.
Beat on low to mix the ingredients together, then mix on high for 5 minutes to combine well.
Add the dry ingredients and beat on low until just combined. Then, beat on high for 3 minutes, scraping down the sides of the bowl as necessary, until the mixture is completely incorporated.
Pour the mixture into your prepared baking tin.
Bake for 40 – 45 minutes until a toothpick inserted in the center of the cake comes out clean. Remove from the oven and allow to cool in the tin for 15 minutes, then remove from the baking tin.
Allow the cake to cool completely before placing it in the refrigerator to chill before frosting.
While the cake is in the refrigerator, cream the butter and cream cheese together until smooth. Add the vanilla and powdered stevia.
Beat on low until combined, then on high for 5 minutes until fluffy. Place in the refrigerator to firm up.
When the cake is chilled, add the frosting and garnish with chopped nuts if desired.