Preheat oven to 200°C. Line a baking tray with baking paper.
To make the roasted red capsicum mayonnaise, brash the whole capsicum with olive oil. Place capsicum on the lined baking tray and roast in preheated oven for 30 minutes or until softened and the skin has blistered. Transfer to a sealed plastic bag (this helps lift the skin) and stand for 20 minutes. Deseed and then peel the capsicum. Reserve the flesh.
Meanwhile, place the egg yolks, lemon juice and Dijon mustard into the bowl of a food processor. Process until the mixture is creamy Add the garlic. With the motor running, gradually add the olive oil, drop by drop until the mixture begins to thicken. Add the remaining oil in a thin, steady stream until well combined. Cut 1 strip from the roasted capsicum flesh and reserve. Add the remaining capsicum flesh, season to taste and process until thoroughly combined.
Bring a large saucepan of water to the boil. Add the asparagus and cook for 4 minutes or until tender crisp. Drain the asparagus in a colander and refresh under cold running water. Drain well. Cover with plastic wrap and refrigerate.
To serve, dice the reserved strip of roasted capsicum flesh and sprinkle over the mayonnaise to garnish. Serve with the asparagus.
