Chop the strawberries into 1/4-inch dice and add them to a glass or ceramic bowl. Add sugar, balsamic vinegar and torn basil leaves. Gently toss to combine and set aside to macerate for 15 to 20 minutes.
Lightly brush the toasted crostini slices with the macerating liquid to sweeten. Spread 1 tablespoon of ricotta on each toast and then top with 1 tablespoon of macerated strawberries. Drizzle each crostini with remaining liquid and sprinkle with just a pinch of fresh ground black pepper.