Preheat the oven to 450 degrees. Pour 1 tablespoon olive oil on a baking dish. Place the cauliflower florets on the baking dish. Drizzle with the remaining olive oil and sprinkle with salt and pepper. Bake for 20-25 minutes, turning the cauliflower halfway through baking.
Meanwhile, melt the butter in a small skillet over medium heat. Add in the pumpkin seeds and cook, swirling pan occasionally, until the butter is browned. This will take 6-8 minutes.
Remove from heat and add the garlic, red pepper flakes, and lime juice and stir.
Arrange the cauliflower on a platter and drizzle with the brown butter and pumpkin seeds. Sprinkle with cilantro.