Combine milk and bread in a bowl, set aside until bread is soft (8-10 minutes). Squeeze milk from bread (discard milk), transfer to a food processor, add almonds and garlic and process until finely chopped. With motor running, gradually add oil, then 200ml iced water. Add sherry vinegar, season to taste and refrigerate until well chilled (1-2 hours).
Meanwhile, for parsley oil, process parsley and garlic in a blender until coarsely chopped. With motor running, gradually add oil and process until very smooth. Transfer to a muslin-lined sieve placed over a bowl and set aside until all parsley oil has drained (5 minutes, discard solids).
Ladle chilled ajo blanco into two small serving glasses, drizzle with parsley oil and serve scattered with almond flakes.