Preheat oven to 350 degrees Fahrenheit. Line baking sheets with Gefen Parchment Paper. Set aside.

In a small bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

In the bowl of an electric mixer (or in a large bowl using a hand mixer), cream together the butter and the sugar. Add the egg, egg yolk and vanilla, beating until fully combined. Beat in the tahini until fully incorporated.

Stir the dry ingredients into the creamed butter/tahini mixture, just until the flour is no longer visible.

Shape balls of dough, each 20 grams or one tablespoon. Coat each in sesame seeds if using. Slightly flatten the ball into a thick pancake and use your thumb to create a deep imprint in the middle of each cookie.

Place between 1/4 teaspoon to 1/2 teaspoon of lemon ginger jam in the center of each cookie.

Bake for 15 to 17 minutes. The edges should be lightly browned.

Allow the cookies to cool completely on the pan.

Once cooled, add an additional small dollop of jam to the center of each cookie.