How to Make It
Preheat oven to 325°F. Lightly coat a 9- x 5-inch loaf pan with cooking spray. Line pan with parchment paper, allowing 2 inches of overhang on all sides. Whisk together gluten-free flour and baking powder in a medium bowl; set aside. Beat almond flour, sugar, and butter in bowl of a heavy-duty stand mixer on medium speed until well combined and crumbly, about 4 minutes. Gradually add eggs, beating just until combined. Stir in vanilla extract and salt. Add flour mixture, beating on low speed just until incorporated.
Pour batter into prepared pan. Sprinkle halvah and sesame seeds evenly over batter. Bake in preheated oven until deep golden brown and top springs back gently when pressed, 55 minutes to 1 hour. (A wooden pick inserted in cake will not come out clean.) Transfer pan to a wire rack, and let cool slightly, about 30 minutes. Using parchment paper as handles, lift loaf from pan, and cool completely on wire rack, about 1 hour. Slice and serve.