Bake the cauliflower: Preheat the oven to 400 degrees F. Line a baking sheet with foil.
Place the cauliflower on the prepared baking sheet, evenly drizzle the 1/4 cup oil over the top, and sprinkle with the salt. Bake for 40 to 50 minutes, until the cauliflower is golden brown and fork-tender.
Meanwhile, make the chutney: In a large nonstick skillet over medium-high heat, warm the 3 tablespoons of olive oil. Once the oil begins to shimmer, add the fenugreek and peppercorns and toss in the oil for 1 to 2 minutes, until the fenugreek has lightly browned. Add the green chile, garlic and onion and cook until the onion has become translucent, 3 to 4 minutes. Add the peas and cook until they are warmed through, 3 to 4 minutes more. Add 1/2 cup water and bring the mixture to a boil. Immediately remove the pan from the heat and stir in the salt and cilantro. Let cool for 5 minutes, then transfer to a blender. Add the walnuts and lime juice and blend into a smooth paste.
On a plate, make a pool of chutney and top with the whole cauliflower. To serve, slice the cauliflower into "steaks" of your preferred size and top with more chutney as desired. Garnish with lime wedges.