Preheat oven to 350°F/180°C. Line a cookie sheet with parchment paper.
Make lemon sugar: In a large mixing bowl, add sugar and lemon zest. Use your fingers to mix the lemon zest into the sugar.
Mix wet ingredients: Add softened butter to the lemon sugar. Cream together (either with a mixer or whisk) until uniform.
Add peanut butter and mix until uniform.
Add remaining wet ingredients and mix until well combined.
Add dry ingredients: Add rice flour, glutinous rice flour, baking soda, and baking powder. Mix until mostly combined, then add sesame seeds and nori and mix to distribute. The dough will appear crumbly. Use your hands to form a ball of dough - the dough should hold together easily when you pinch it with your hands.
Roll dough: Roll about 2 tbsp of dough into a ball and place on your prepared cookie sheet. Leave about 2 inches of space between each cookie as they will spread slightly.
Shape dough: Use the palm of your hand to flatten the dough balls. For thick, chewy cookies, just slightly flatten the dough so it's a fat disc shape rather than a ball. For thinner, crispier cookies, flatten into a thin disc.
For thick, chewy cookies: Bake for 9 minutes, bang the cookie sheet on the counter or oven rack (from about 4 inches up), bake another 3 minutes, then bang the cookie sheet again. Let the cookies cool for about 2 minutes on the sheet, then transfer to a wire rack to finish cooling.
For thin, crispy cookies: Bake for 12 minutes. Let the cookies cool for 2 minutes on the cookie sheet, then transfer to a wire rack to finish cooling.
Notes
Miso: Feel free to use any type of miso you like. I used red miso since I prefer a more savory flavor. White miso will be a bit sweeter and less savory.Nori: I just cut up a nori sheet, though you can also buy shredded nori. You can omit the nori if you'd like. You don't really taste it much, but I think it adds a fun element and reminds me more of senbei.