Ingredients

   
  Cookies
185g AP flour
2g baking soda
9g matcha
13g vanilla extract
113g unsalted butter, softened
15g peanut butter (or tahini)
150g granulated sugar
50g brown sugar
3g salt
1 large egg
  Frosting
150g granulated sugar
24g AP flour
  pinch of salt
237g whole milk
227g unsalted butter, softened
4g vanilla extract

Steps

  1. Whisk together flour and baking soda in a medium bowl.

  2. In a large bowl, stir the matcha and vanilla into a paste with a spatula. Add butter, peanut butter, both sugars, and salt. Beat until pale green and fluffy. Switch to a whisk and beat in the egg until smooth.

  3. Fold the flour mixture into the wet ingredients until just combined. Refrigerate the dough, uncovered, while the oven heats.

  4. Heat oven to 350°F. Line baking sheets with parchment.

  5. Scoop 1½-tablespoon rounds and space them a couple inches apart. Bake until puffed and no longer wet-looking on top, about 15 minutes. Cool completely on the pan.

  6. Make the frosting: in a medium saucepan off the heat, whisk together sugar, flour, and salt. Whisk in the milk until smooth. Cook over medium heat, whisking constantly, until it bubbles, about 4 minutes, then keep whisking as it boils until thick like pudding, about 2 minutes more.

  7. Transfer the hot mixture to a stand mixer with the paddle. Beat on high until the bowl feels cool to the touch, up to 10 minutes.

  8. With the mixer on medium-high, add the softened butter 2 tablespoons at a time, beating smooth before each addition. Add vanilla, then beat on high until very fluffy, 3–5 minutes.

  9. Frost each cooled cookie. Serve immediately.

Analysis

Total batter weight: 590g (cookie dough; ermine frosting excluded — see below)

Component Amount %
Structure solids (flour) 185g 31.4%
Fat (butter, peanut butter, egg) 113g 19.2%
Sugar (granulated + brown) 200g 33.9%
Liquid (vanilla, butter water, egg water) 66g 11.2%
Egg/protein 26g 4.4%

A soft, cakey sugar cookie: structure at 31% with relatively modest fat (19%) and high sugar (34%) gives a tender, puffy crumb rather than a chewy one — the recipe even bakes them just until the tops lose their sheen. The frosting is excluded from these numbers: it’s an ermine buttercream applied after baking (roughly 227g butter + 150g sugar + 237g milk + 24g flour), a finishing layer, not part of the dough.

Notes

  • The frosting is an ermine (boiled-milk) buttercream — cooking the flour and milk into a pudding first, then whipping with butter. It’s silky and not too sweet, which is what gives these the milky “latte” character. Don’t skip the full cool-down before adding butter or it will split.
  • The dab of peanut butter (or tahini) adds body and a subtle nuttiness without reading as peanut. It’s the signature touch here.
  • Use a matcha you’d actually drink — the flavor carries the whole cookie. Bump to 12g if you want it more assertive against the sweet frosting.
  • Unfrosted cookies keep in an airtight container 2–3 days. Frost only what you’ll eat that day; the buttercream is best fresh.
  • The cookies bake up soft and cakey, not chewy — that’s intended. Pull them while the tops just lose their wet sheen.
  • For a matcha-on-matcha look, dust the frosted cookies with a little extra matcha or add sprinkles.