Prep: Preheat oven to 350°F. Grease/line two 9x5 inch loaf pans.
Dry ingredients: Whisk flour, baking powder, and salt. Set aside.
Cream: Beat softened butter and sugar until smooth and creamy, about 3-4 minutes.
Eggs: Add beaten eggs gradually and beat until incorporated.
Wet ingredients: Add sour cream, vanilla, and black tahini. Mix until combined.
Combine: Add dry ingredients and mix on low. Slowly pour in milk in intervals mixing just until combined. Do not overmix. Batter will be thick.
Bake: Divide between pans. Bake 60-75 minutes until toothpick comes out clean. Tent with foil if browning too quickly.
Cool: Cool in pan 15-20 minutes then turn out onto wire rack and cool completely.