Preheat the oven to 325°F. Spread ½ cup raw walnuts halves on a sheet pan and roast until fragrant and lightly toasted, 11 to 14 minutes. Remove from the oven and let cool.
Increase the oven temperature to 400°F. Cut 1 1-to-1½ pound honeynut or butternut squash in half lengthwise and scoop out the seeds. Drizzle with 1 tablespoon extra virgin olive oil and sprinkle the cut sides with 1 teaspoon fine sea salt. Place the squash cut-side down on a baking sheet and roast until tender, 25 to 30 minutes for honeynut squash or up to 45 to 55 minutes for butternut squash. Remove from the oven and let cool for 30 minutes.
Place the cooled, roasted walnuts in a mortar and pound, breaking them up into small pieces about the size of pebbly sand, leaving some bigger pieces for texture.
Scoop the roasted squash flesh into a bowl along with 1 cup labneh, 1 grated garlic clove, ⅔ of the toasted walnuts, and the remaining 1 teaspoon fine sea salt. Mix with a fork, mashing the squash so that it still has a rustic texture.
Taste and adjust sweetness with 1 to 2 teaspoons mild honey, if desired, and salt, if necessary.
To prepare the tadka, thinly slice the remaining 2 garlic cloves. Then, heat the remaining 3 tablespoons extra virgin olive oil in a small skillet or over medium heat. Add the sliced garlic, 1 teaspoon caraway seeds and 1 teaspoon fennel seeds, and cook, stirring or swirling frequently, until the garlic turns light golden, 1 to 3 minutes. Turn off the heat, add 1 teaspoon Kashmiri chili powder, and mix to combine.
To serve, transfer the dip to a shallow serving bowl and create a swoosh pattern on the surface with the back of a spoon. Spoon the prepared tadka over the dip, sprinkle with the remaining ⅓ of the crushed toasted walnuts, and garnish with a smattering of flaky sea salt.
