How to Make It
Preheat the oven to 450°. Set the pork fat side up on a rack set over a rimmed baking sheet. Rub the roast with 2 tablespoons of the oil and the rosemary and thyme; season with salt and pepper. On another sheet, toss the squash, garlic, onion and bell pepper with 2 tablespoons of the oil; season with salt and pepper.
Roast the pork in the middle third of the oven and the vegetables in the bottom third for about 40 minutes, until the squash is tender. Transfer the vegetables to a rack to cool. Turn the oven down to 375° and roast the pork for about 45 minutes longer, until an instant-read thermometer inserted in the thickest part registers 135°. Transfer the pork to a work surface and let rest for 15 minutes.
Meanwhile, on another baking sheet, toss the bread with 1 tablespoon of the oil and bake until golden, 12 minutes.
When the squash is cool, scoop the flesh into a food processor. Peel the bell pepper and discard the skin. Add the roasted pepper, garlic and onion to the processor along with the croutons, almonds, vinegar and piment d’Espelette. Puree until almost smooth. With the machine on, slowly stream in the remaining 1/4 cup of olive oil. Season the puree with salt and pepper.
In a bowl, whisk the first 6 ingredients. Add the greens and season with salt and pepper. Transfer to a serving bowl and garnish with more fresh horseradish.
Carve the pork and serve with the squash puree and dandelion salad.