Preheat oven to 350F.  Prepare a 8x5" loaf pan with parchment paper and lightly coat with nonstick spray.  Sprinkle sides and bottom of pan with some sesame seeds and coconut sugar and shake around to coat.

Whisk flours, baking powder, cardamom and baking soda in a medium bowl to combine.

In a separate bowl, whisk yogurt and tahini until smooth.

Using an electric mixer on medium-high speed, beat eggs, vanilla and 1 cup coconut sugar in a large bowl until eggs are pale and thick.  

Reduce speed to medium and gradually stream in the avocado oil.

Reduce speed further to low and add dry ingredients in 3 additions, alternating with yogurt mixture in 2 additions.  Beat after each addition until fully incorporated.

Scrape half the batter into a bowl and set aside.  Add the 2tbs sesame seeds and cocoa powder to the other half and mix until well combined.  

Alternating between batters, spoon large dollops into the prepared pan, then drag the tip of a knife through the batter to swirl.  Sprinkle with more sesame seeds and a little more coconut sugar.

Bake for 30-40 minutes until a toothpick comes out clean.  Transfer to a wire rack and let cool in pan for about 10 minutes.  Then remove from the pan and place onto the rack to cool completely.