Preheat the oven to 350°F (180°C). Place all the cookie dough ingredients except the granulated sugar into a plastic bag and knead until combined.

Once the dough comes together, it's ready.

Divide the dough into 4 equal pieces (about 20g each). Roll each piece into a ball, then flatten between the bag to about the size of the muffin cup opening.

You can just press the dough out with your hands—no need for a rolling pin.

Using the back of a knife, gently press a crisscross pattern onto the dough through the bag. It's okay if it cuts a little.

Add all the muffin batter ingredients to a bowl and mix with a large spoon until combined.

The batter should be smooth and slightly thick.

Divide the muffin batter evenly among muffin cups. (I used heatproof silicone cups for this.)

Sprinkle granulated sugar over the surface of the cookie dough. If you don't have granulated sugar, regular sugar works, or you can skip this step.

Place the cookie dough rounds on top of the muffin batter. Just set them on top—no need to press down. Bake at 350°F (180°C) for about 20 minutes or until done.

If the tops are browning too quickly, cover with aluminum foil partway through baking.

When the muffins are puffed and golden brown, they're done. If you're worried they're underbaked, insert a toothpick—if it comes out clean, they're ready.

The cookie layer is crunchy. The muffins may have a few air pockets but are fluffy inside.