• Preheat the oven to 350° F and line two baking sheets with parchment paper

For the sesame paste:

• Toast black sesame seeds in a dry skillet on low heat for 2-3 minutes, stirring frequently to prevent burning.
• Pour sesame seeds into a small food processor or spice grinder and blend until well broken down, 3-5 minutes. Stop machine and scrape down sides as needed.
• With motor running, add honey, sesame oil, and water. Continue to blend until mixture forms a fine paste, stopping to scrape the sides every once in a while. It may take a few minutes to get it to a nice texture; be patient and keep processing until the mixture is fairly smooth (some chunks are fine).

For the cookie dough:

• In a large bowl, whisk together flour, baking powder, and salt.
• Cream butter and sugar until soft and fluffy, about 2 minutes. Add egg and vanilla; beat until combined.
• Stir in dry ingredients just until combined.

For the strawberry powder:

• Crush strawberries into a powder using a food processor or spice grinder. Alternatively, you could place the strawberries in a sealed bag and run a rolling pin over them a few times. I like a slightly uneven texture here, with a few larger strawberry chunks left behind.

To swirl the batter:

• Place about ⅓ of the cookie dough into a separate bowl. Dot little bits of sesame paste onto this dough and swirl it together lightly.
• Fold the remaining ⅔ of the dough with the strawberry powder until mostly combined.
• Dot the strawberry dough with about half of the black sesame swirl cookie dough. Fold it together once or twice. Dot the remaining sesame dough on top and fold in again, swirling the two doughs together very lightly. For the best swirl, don't mix them too much!
• Use a small spring-loaded scoop to make cookie dough balls. Dip bottoms of each cookie in black sesame seeds. Place cookies on prepared baking sheets, about two inches apart, and flatten them slightly with a measuring cup or the palm of your hand.
• Bake until edges are lightly golden and centers are baked through, about 11-13 minutes.