For best results, toast the baguette just until crisp so it stays crunchy under the topping but doesn’t become too hard to bite, and allow it to cool so the cream mixture doesn’t melt. Smoked salmon can be quite salty, so taste before adding extra salt and balance flavors with lemon juice and fresh herbs. Assemble the crostini shortly before serving to prevent sogginess, or keep all components prepared separately and build them at the last minute. You can vary the herbs, swap cream cheese for mascarpone, or add thin cucumber slices under the salmon for extra freshness and texture.