Fill a medium bowl with ice and cold water, and set it aside.

Bring a saucepan of salted water to a boil over high heat. Add the peas and cook until the water returns to a boil. Drain, and immediately submerge the peas in the ice water. When they have cooled, drain them again and set them aside.

Preheat an outdoor grill or a grill pan to medium-high.

Slice the baguette into 3-inch-long oval slices, 1/4 inch thick. Brush one side of each slice with the olive oil, and season them with 1/8 teaspoon salt and 1/8 teaspoon pepper. Grill on both sides until toasted. Set aside.

On a cutting board, sprinkle 1/4 teaspoon salt over 1 teaspoon of the minced garlic. Chop the garlic and mash it with the flat side of your knife until the mixture forms a paste. In a small bowl, combine the garlic paste, ricotta, 1 tablespoon of the extra-virgin olive oil, the 1 tablespoon mint, the shallot, and 1/2 teaspoon pepper. Mix well, and set aside.

In another small bowl, mash the spring peas with the back of a fork until there are no whole peas; you should have a mixture of pea halves and paste. Add 1/8 teaspoon salt, 1/8 teaspoon pepper, 1 teaspoon minced garlic, 2 tablespoons extra-virgin olive oil, the 1 teaspoon mint, and the Parmesan and basil. Stir gently to combine.

Spoon about 1 tablespoon of the ricotta mixture onto each crostini, and spoon about 2 teaspoons of the pea mixture on top of the ricotta mixture. Repeat with the remaining crostini. Drizzle extra-virgin olive oil over the top as desired, and serve.