How to Make It
Preheat the oven to 400°. On a parchment paper-lined baking sheet, toss the grapes with the vinegar, rosemary sprigs and 2 tablespoons of the olive oil. Season with salt and pepper and toss to coat. Roast for about 15 minutes, stirring occasionally, until the grapes are softened and the skins start to pop.
Meanwhile, spread the pine nuts in a pie plate and roast in the oven for 6 to 8 minutes, until golden. Brush the baguette slices with the remaining 1 tablespoon of olive oil. Arrange on a baking sheet and toast for about 8 minutes, until golden and crisp.
To assemble the crostini, dollop 1 tablespoon of the ricotta onto each toast. Spoon the warm grapes on top and sprinkle with the pine nuts. Arrange on a platter and top with a drizzle of honey and some lemon zest. Sprinkle the crostini with salt and garnish with chopped rosemary.