2. Wipe the dried tangerine peel into thin pieces, mix with flour, cocoa powder and cake baking powder, add milk and cake paste and stir to form dough.

3. Cut the butter into small pieces, soften it and gently stir it into the mud.

4. Take a rectangular baking tray with a volume of about 1.5 liter, coat it with oil to prevent adhesion, and put it into the dough to flatten it.

5. Preheat the oven to 175℃ and bake in the oven for 60 minutes.