Preheat oven to 400° (F) and adjust rack to the middle position. Line a large sheet pan with foil or parchment.
Cut the delicata squash crosswise and remove the seeds. Slice the squash thinly (no need to remove the skin because it is edible). Toss the squash with the neutral oil, ¼ tsp Kosher salt, and a few cranks of black pepper. Spread the squash evenly onto a sheet pan and roast for until soft and slightly browned, 20-25 min.
Squeeze the half lemon into a pint of water. Julienne the apples and soak in the lemon water.
Press the halloumi between a few pieces of paper towel to absorb any exterior moisture. Dice the halloumi and toss with just enough olive oil to coat the cubes. In a nonstick pan over medium heat, brown the halloumi cubes in batches.
When the delicata squash is cool enough to handle, combine it with the quinoa, apples (drain first), and broccoli slaw. Dress and season to taste. Top with the halloumi cubes and garnish with the pepitas.
Place Dijon mustard, maple syrup, garlic and vinegar in a pint sized mason jar. Using an immersion blender (you could also use a regular, top loading blender), blend until combined. While blending, slowly drizzle in the grapeseed oil first, then the olive oil, to emulsify into the dressing. Season to taste with Kosher salt and black pepper.
