Preheat oven to 350 degrees F and line a baking sheet with parchment paper.

In a medium bowl, combine walnut halves, maple syrup, and olive oil.

Stir the mixture well to ensure the walnuts are evenly coated.

In a small bowl, whisk together ground cinnamon, coarse salt, and ground cloves.

Add the spice mixture to the walnuts and stir until the spices are evenly distributed.

Spread the spiced walnuts in a single layer on the prepared baking sheet.

Bake for about 10 minutes, or until fragrant and toasted.

Remove from oven and let the walnuts cool completely on the baking sheet.

Store in an airtight container at room temperature.