1. Bring a large pan of heavily salted water to the boil. Break the cauliflower into florets and prepare a large mixing bowl with iced water. Once the water is boiling, add the cauliflower florets (in batches if necessary) and cook for 5 mins. After 5 mins, transfer to the iced water for a few mins. Once cool, remove and pat dry on a tea towel.
2. In a large mixing bowl, combine the flour, cornflour, baking powder and a generous pinch of salt and pepper. Slowly add the sparkling water and mix well with a whisk to form a paste. Now add the beer until a liquid batter forms. Set aside.
3. Bring the milk to a simmer in a small saucepan and then add the Gorgonzola. Cook over a low heat for a couple of mins until the cheese has melted. Mix well with a spatula or whisk until smooth (you can even use a hand blender to create an extra-smooth fonduta). Add the cayenne pepper and a pinch of salt, mix through and check the seasoning, then set aside in a warm place.
4. In a heavy-bottomed saucepan, heat 5cm of vegetable oil until it reaches 180°c. No thermometer? Have a look here for a handy guide on knowing when your oil is ready for frying.
5. Dust the cauliflower florets in some plain flour and then dip in the beer batter. Drain any excess and then carefully transfer to the hot oil. Cook for a few mins, turning over halfway through. When golden brown, use a slotted spoon or spider to transfer to a cooling wire rack to drain the excess cooking oil. Serve immediately alongside the warm fonduta.