Step 1

For the aioli, whiz egg, garlic, juice and 1/2 teaspoon salt in a blender. With the motor running, add olive oil, then vegetable oil, in a steady, barely-there trickle until the mixture is thick and smooth. Refrigerate, covered, for 3-4 days until needed.

Step 2

Cut straight down the sides of the sweet potato, removing the "hips". Peel and cut into 2cm-thick slices, then cut each slice into 2cm cubes. Cook in a steamer over a pan of simmering water for 10-15 minutes until tender. Cool to room temperature and season well.

Step 3

Sizzle chorizo in a non-stick pan over high heat for 40 seconds each side or until crisp. To serve, top each sweet potato cube with a piece of chorizo, a dab of aioli and a coriander leaf.