Method

• 1.
  For the sweet potato chips and onion rings, place sweet potato and onion in separate bowls. Divide buttermilk, thyme and 1 tsp each salt flakes and freshly ground black pepper evenly between bowls, stir to combine, then cover and chill overnight to marinate.
• 2.
  To make the dip, place garlic and milk in a saucepan over high heat and bring to the boil. Reduce heat to low and simmer, stirring occasionally, for 10 minutes or until garlic has softened and absorbed most of the milk. Remove garlic with a slotted spoon and drain on paper towel.

• 3.
  Return drained garlic to the cleaned pan with oil and cook over low heat, stirring frequently, for 25-30 minutes or until garlic is golden. Add vinegar, chilli and anchovy, and cook, stirring occasionally, for 10 minutes or until chilli has softened. Transfer garlic mixture to a blender with spinach and flat-leaf parsley and whiz until smooth. Transfer to a bowl, cover surface directly with plastic wrap and chill until needed.
• 4.
  When ready to serve, to cook the sweet potato, combine rice flour and polenta in a bowl. Half-fill a deep-fryer or large saucepan with sunflower oil and heat to 180°C (a cube of bread will turn golden in 90 seconds when the oil is hot enough).
• 5.
  Working in batches, remove sweet potato from buttermilk mixture, shaking off excess. Add to polenta mixture and toss to coat. Deep-fry sweet potato, turning halfway, for 3-4 minutes or until golden and crisp. Remove with a slotted spoon, drain on paper towel and scatter with salt flakes while hot. Repeat with remaining sweet potato. For onion rings and thyme, repeat sweet potato cooking method.
• 6.
  Transfer dip to a serving bowl and scatter with baby parsley and extra chilli. Serve with deep-fried sweet potato chips, onion rings and thyme sprigs.