Heat oven to 425° F
Place the squash in a bowl and add the coriander and cumin (The cumin and coriander could easily be replaced with a spice blend like ras el hanout, baharat, garam masala or five-spice powder). Drizzle generously with olive oil, season with salt and pepper, then toss until the squash is evenly coated. Arrange in a single layer on a sheet pan and roast until tender and golden, 25 to 30 minutes.
Meanwhile, prepare the whipped feta: Place the feta, garlic, lemon juice and 3 tablespoons milk into a small blender or food processor; purée until completely smooth, adding another tablespoon of milk if it’s too thick or chunky. The texture should be thick and velvety but easily spreadable (similar to hummus). Stir in the lemon zest and season with lots of black pepper. Spread the whipped feta onto a large serving plate or platter.
Place the squash on top of the whipped feta and then scatter the pistachios (and herbs and crushed red pepper if using) over the squash. To finish, drizzle with olive oil and season with salt and pepper.