Warm the chicken broth and red chilli flakes in a medium saucepan over medium-high heat until the broth boils. Add the peas and cook until tender, about 5 minutes. Drain the peas in a mesh sieve.
Place the peas in a food processor with the mint, salt, and pepper. Puree the pea mixture. Place the pea puree in a medium bowl and refrigerate until cool, about 30 minutes.
Preheat the oven to 190°C/gas mark 5. Place the baguette slices on a greaseproof paper-lined baking sheet in a single layer. Bake in the oven until toasted and golden around the edges, about 10 minutes.
Whilst the crostini are still warm, drizzle the tops with extra-virgin olive oil. Using a whole clove of garlic in your fingertips, rub the top of the crostini a few times to give a hint of garlic.
To finish, whip the cream until stiff peaks form. Fold the whipped cream into the pea puree. Top each of the crostini with about one tablespoon of pea puree. Sprinkle with a bit of the diced prosciutto. Serve immediately.