Bring a pot of water up to a boil and salt generously. Trim asparagus and add to water. Blanch, uncovered, until tender (check by tasting – time will vary depending on thickness of asparagus). Once tender drain and shock in a bowl with ice and water to halt cooking. Strain and chill until ready to serve.
Stir almonds, milk and 1 cup (250 ml) water together and chill overnight (or for at least 6 hours).
Slice garlic and pour boiling water to cover. Let sit for 15 minutes, then drain (this blanches the garlic to take the edge off).
In a food processor, blend garlic with almond mixture, breadcrumbs and vinegar until smooth. Pour in olive oil in a thin stream while blending. Adjust thickness to sauce consistency with water, if necessary. Season to taste and chill until ready to serve. Sauce should be served at room temperature.
To serve, preheat grill to medium high. Toss blanched asparagus in olive oil, salt & pepper and place on grill. Turn once or twice until asparagus is warm and shows grill marks. Remove from heat and serve with sauce