Preheat oven to 325F and grease a large bundt pan very well.
In a medium bowl, whisk together the almond flour, coconut flour, protein powder, baking powder, and salt.
In a large bowl, beat the butter with the sweetener until lightened and fluffy, about 3 minutes. Beat in the eggs one at a time, scraping down the sides of the bowl and the beaters as needed. Add Vanilla.
Beat the almond flour mixture in two additions, alternating with a half cup of almond milk. Beat in additional almond milk if your batter is very stiff and thick. Stir in pecans.
Dollop the batter into the prepared bundt pan and smooth the top. Bake 50 to 60 minutes, until cake is golden brown and the top is firm to the touch. A tester inserted in the center should come out clean.
Remove and let cool 15 minutes in the pan, then transfer to a wire rack to cool completely.
In a small saucepan over low heat, melt butter. Remove from heat and stir in powdered sweetener and whipping cream. Drizzle over cooled cake. Sprinkle with pecan halves.