Preheat the oven to 375 degrees F.

In a small bowl, combine cinnamon, cumin, cayenne, and salt.

Rub the spice mixture all over the pork loin.

Heat vegetable oil in a large saute pan over medium-high heat.

Brown the pork loin on all sides until golden.

Transfer the browned pork loin to a sheet tray, fat side up.

In a food processor, combine onion, garlic, ginger, cilantro, and lime zest.

In the same saute pan, add olive oil and the onion mixture.

Cook until the onion mixture softens.

Stir in bread crumbs and cook for 1-2 minutes.

Season the herb crust with salt.

Spread Dijon mustard on top of the fatty layer of the pork.

Press the herb crust firmly into the mustard layer.

Bake until the internal temperature reaches 160 degrees F (about 30 minutes).

Remove from the oven and let rest, covered, for 5-10 minutes.

Slice the roast and arrange on a serving platter.

Serve immediately.