Preheat oven to 400ºF.

Place a large skillet over medium-high heat with 2 turns of the pan of EVOO, about 2 tablespoons. Season the pork with salt and pepper and sear in the hot pan until golden brown on all sides, remove from the skillet and let cool.

While the tenderloin is searing, run your knife through the mango chutney to insure that there are no large mango pieces. Lay the puff dough down onto the countertop and cut it in half lengthwise. Divide the mango chutney between the two halves of pastry and spread out to cover it from edge to edge.

Place each seared tenderloin on the center of each chutney-coated pastry half. Roll the pastry over the tenderloin until it meets its opposite edge and pinch it closed to make a long tube shape. Pinch the short ends together to seal the tenderloin inside the pastry completely. Place the meat, seam-side down, on a baking sheet and bake in the hot oven until the dough is deep golden brown, about 25 minutes.

When the meat has about 10 minutes of baking time left, place the pan that the pork was cooked in back on the heat with 2 turns of EVOO, about 2 tablespoons. Add the onions to the pan and cook until tender, 3-4 minutes. Add as much of the spinach as you can fit in the pan, continue adding spinach as the batch in the skillet wilts down. Season with some salt and pepper and toss to combine.

With a serrated or really sharp knife, slice the Pork Wellington and serve with the wilted spinach alongside.