Because they use modernist ingredients, these amounts are given in metric by weight. For more information on how to measure modernist ingredients check out this article.
200g onion, 1 medium, diced
Heat some oil in a pan over medium heat. Add the onion and cook until it has softened. Add the garlic, orange peel, and thyme then cook until the garlic has softened. Add the chicken stock and white beans then bring to a simmer. Cook until the beans are very tender, about 10 minutes. Remove from the heat and let cool.
Once the cooked white bean mixture has cooled, stir in the lemon juice then puree it well. Add the cream and puree to mix. If the puree needs to be thicker, some xanthan gum can be added, about 0.1% to 0.3%.
Because xanthan gum is a modernist ingredient, the amounts for this component are given in metric by weight. Learn more about how to measure modernist ingredients in this article.
The white bean puree will last in the refrigerator for several days and can be served cold or reheated.
Combine the olive oil and rosemary in a pot set to low heat. The oil should be just below a "fry" and if the rosemary starts to sizzle turn it down or partially remove it from the heat.
After 30 to 60 minutes the oil should have taken on most of the rosemary flavor. At this point, stir in the mono and diglyceride flakes, remove the oil from the heat and let it cool slightly.
Add the rosemary oil and parsley to a blender and puree until smooth. For a more refined presentation you can strain the oil before using it.
Place the crostini base on a serving plate, or individual plates. Add a spoonful of white bean puree on top. Dot with two to three drops of the rosemary oil and grate some fresh lemon zest on top.