Pão de queijo

Step 1: Heat the oven to 400°F (350°F fan) and line a large baking tray with baking paper. Put the 5 ½ oz sour cassava starch (polvilho azedo) and 3 ½ oz tapioca starch (polvilho doce) in a large heatproof bowl and break up any lumps with your fingers.

Step 2: Bring the ½ cup whole milk, ¼ cup water, ¼ cup sunflower oil and 1 tsp salt to a rolling boil in a small pan over a medium heat. Watch it: milk boils over in seconds.

Step 3: Pour the boiling liquid all over the starch at once and stir hard with a wooden spoon. It will look lumpy and patchy, then come together into a sticky, translucent-looking mass. This is the escaldado; it should feel like thick glue.

Step 4: Leave it to cool for 10 minutes, until you can hold your finger in it comfortably. If it's too hot, the eggs will scramble.

Step 5: Add the 2 eggs a little at a time, working each addition in with the spoon or your hand before adding more. At first it seems the dough will never take the egg; keep squeezing and folding and it becomes smooth, soft and sticky, like a thick choux paste.

Step 6: Knead in the 3 ½ oz Parmesan-style hard cheese and 2 ⅝ oz low-moisture mozzarella until evenly mixed. The dough should be soft enough to shape but hold its form. If it's too runny to roll, add a spoon of tapioca starch; if it cracks, add a teaspoon of milk.

Step 7: Oil your hands and roll the dough into balls the size of a walnut (about 25 g each), setting them 4 cm apart on the tray. You can freeze the raw balls at this point and bake from frozen, adding 5–8 minutes.

Step 8: Bake for 22–25 minutes, until well puffed, cracked on top and golden at the edges; don't open the oven in the first 15 minutes or they can sink. They should sound light when tapped. Eat warm, with strong coffee.