In a small saucepan, heat the blackberries over a low flame.

Gently smash the blackberries down with a fork as they cook down.

Mix in the honey and lemon zest and continue cooking until blackberry mixtures has thickened

Heat a grill or grill pan over medium.

Lightly brush the bread with olive oil. Grill olive oil side down for a few minutes until grill marks are achieved.

Repeat on the other side.

While the crostini is still warm, add a slice of fresh mozzarella.

Then, spoon some of the blackberry mixture on top. Top with some fresh sage and serve.