Preheat oven to 180°C. Line a 16cm x 26cm slice pan with foil, allowing the sides to overhang. Place stock in a medium saucepan. Bring to a simmer over high heat. Gradually add the polenta in a thin, steady stream, stirring constantly. Cook, stirring, for 5 mins or until the mixture boils and thickens. Pour into the lined pan and smooth the surface. Set aside to cool slightly. Place in the fridge for 30 mins or until set.
Meanwhile, line a baking tray with baking paper. Place tomatoes on the lined tray. Roast for 20 mins or until tomatoes begin to collapse. Set aside to cool.
Place the basil, pine nuts, parmesan, garlic and extra virgin olive oil in a food processor. Process until smooth and well combined. Season. Transfer to a small bowl. Add the crème fraîche or sour cream and stir to combine.
Turn the polenta out onto a clean work surface. Use a 7.5cm round pastry cutter to cut out 6 discs. Heat the olive oil in a large frying pan over medium heat. Add the polenta discs and cook for 5 mins each side or until crisp and golden brown. Transfer to a plate.
Divide the polenta among serving plates. Top with pesto, tomatoes and extra pine nuts. Season with pepper.
Serve withbaby rocket leaves and extra virgin olive oil.
Get ahead:Make the polenta, without frying, up to 2 days ahead and the pesto up to 1 day ahead. Cover separately and store in the fridge.
My polenta keeps bubbling over: To stop your polenta spitting and bubbling over, stir it constantly as it cooks. This keeps the mixture at an even temperature, without hot spots.