It’s just that I once visited neighbours who served us a typical French hors d’œuvre: « oeuf dur mayonnaise », which is a boiled egg served with mayo.

Their mayo was firmer than mine and it was not from the egg or the mustard (we use the same Edmond Fallot brand… best Dijon mustard in the universe). As I used Swiss organic colza oil, I asked what she used. In Burgundy, what seed are frequent? Grape seeds, that’s what. It indeed improved my mayo’s firmness. The spoon stands for 2 days in the pot without touching the edge.