Rinse, hull, and slice the strawberries in half and place them in a bowl. Pour in the sugar, balsamic vinegar, and black pepper. Stir well and refrigerate for 4 hours or overnight.
Preheat the oven to 350°. Using a serrated knife cut the baguette on the bias so that your slices are slightly angled and elongated. Arrange the slices on a baking sheet in a single layer. Brush the tops of the bread with olive oil then bake the bread for 12-15 minutes until the slices are toasted. Be careful to not let the bread burn.
Add the mascarpone and lemon juice to a bowl and mix well. Once the bread has cooled, spread the mascarpone mixture on the bread as thin or thick as you prefer. Spoon the strawberries on top and garnish with freshly chopped basil.