Place a drizzle of olive oil in the palm of your hand and rub both of the aubergines. Place on a baking tray and roast whole for 30 minutes until blacked, and soft.
Once cooked, allow to cool and peel away the blackened skin from the flesh. Gently press the aubergine in a sieve, so that excess liquid drains away. Set aside and make the mayonnaise.
In a blender, mix together the egg yolk, mustard, vinegar and a good pinch of salt. With the blender running, slowly add the oil so that it emulsifies. Here is our guide to mayonnaise ,if you run into trouble.
With the blender still running, add the aubergine, bit by bit, till fully incorporated.
Add the garlic to your taste. I find raw garlic a bit too over powering, so only add 1/2 a small clove, finely grated. Add more or less of what you fancy.