Preheat the oven to 450F (use convection if you have it). Line 2 baking sheets with parchment paper.
Divide the carrots onto each baking sheet. Add 2 tablespoons of olive oil and ½ teaspoon of salt to each sheet pan and toss the carrots to coat. Arrange them cut-side facing up with plenty of space between them (otherwise they will steam and not brown). Bake for 15-20 minutes or until charred on the bottom in spots. This may take longer depending on your oven. Set aside to cool.
In a high-speed blender or food processor, add 2 cups of pistachios. Blend or process until a sticky/thick nut butter consistency forms, scraping down the sides as needed. With the motor running, add 2 tablespoons of olive and blend until smooth and silky. Add the remaining 1/4 tsp salt and pulse to combine.
Spread 1 cup of the pistachio butter on to a large serving platter OR if you don’t have that (like me) spread 1/2 cup onto two large plates. Spread and swirl it around using the back of a spoon until most of the plate is coated with a thin layer.
Arrange the cooled or room temp carrots on top, cut side down. Squeeze the juice from one lemon all over the carrots (about 3-4 tablespoons worth). Chop the remaining ½ cup of pistachios. Sprinkle the chopped pistachios, pomegranate seeds and parsley or cilantro over the carrots. Garnish with a drizzle of olive oil, black pepper and flaky sea salt.
Cut the remaining lemon into slices and scatter them on the platter (you’ll want to add a fresh squeeze to your plate!).