Toss the asparagus and oil and sprinkle with salt and pepper on a baking sheet. Roast the asparagus until lightly roasted but still crunchy, about 5 minutes. Cool the asparagus slightly.
Combine 1 cup water, the asparagus, broth and lemon juice in a blender and puree until very smooth, about 2 minutes. Transfer the soup to a medium heavy saucepan and heat the soup. Stir in the mint and lemon zest and sprinkle with salt and pepper.
Divide the soup among bowls and garnish with the Greek yogurt and almonds.