Combine the butter and sugar in a stand mixer on medium speed or in a large bowl with a hand mixer and mix until light and fluffy, about 2 minutes.

Add the the tehina and continue mixing until well incorporated.

Combine the flour, baking powder, and salt in a mixing bowl and whisk together. Transfer to the tehina mixture and beat until just incorporated.

Cover the bowl with plastic wrap and refrigerate for at least 1 hour or overnight. (This dough keeps well in the freezer for a few months.)

Preheat the oven to 350° F. Line two baking sheets with parchment paper. Drop the batter by the heaping tablespoon onto the prepared baking sheets. Sprinkle each cookie with black sesame seeds if using.

Bake until the cookies are light brown around the edges and set, about 15 minutes. Let cool on the baking sheet for 10 minutes, then transfer to a wire rack to cool completely.

The cookies can be stored at room temperature in an airtight container for 1 week.