Preheat your oven to 400°F and line a large rimmed sheet pan with parchment paper for easy cleanup.
Chop the broccoli and cauliflower into bite-sized florets and slice the chicken sausage into half-inch rounds.
Arrange the sausage and vegetables on the sheet pan, then drizzle with the olive oil.
Evenly sprinkle the cumin, coriander, turmeric, smoked paprika, cayenne, sea salt, and black pepper over the top.
Use your hands or tongs to toss everything thoroughly, ensuring every piece is well-coated in the aromatic spice oil.
Spread the mixture into a single even layer to ensure the vegetables roast and crisp rather than steam.
Roast in the center of the oven for 20 to 25 minutes, tossing halfway through, until the sausage is browned and the vegetables are tender.
Remove the pan from the oven and immediately drizzle the fresh lemon juice over the hot ingredients to brighten the flavor profile.
Garnish the entire pan with freshly chopped parsley and serve warm.