Step 1: Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Step 2: In a large bowl, toss the cubed sweet potatoes, broccoli florets, sliced red onion, and tempeh triangles with olive oil, salt, and pepper until evenly coated.
Step 3: Spread the mixture in a single layer on the prepared baking sheet, ensuring space between pieces for roasting.
Step 4: Bake for 25-30 minutes, tossing halfway through, until the vegetables are tender and the tempeh is golden brown.
Step 5: While the vegetables roast, prepare the sauce by whisking together the tahini, maple syrup, lemon juice, and cinnamon in a small bowl.
Step 6: Gradually add warm water to the sauce until it reaches a smooth, drizzling consistency.
Step 7: Remove the pan from the oven and drizzle the cinnamon tahini sauce generously over the roasted tempeh and vegetables before serving.