Preheat your grill to medium-high heat and your oven to 425°F for roasting the broccoli.
Slice the tempeh into 1/4 inch thick slices and lightly score both sides to help absorb the marinade.
Marinate the tempeh slices in a mixture of lemon juice, salt, and pepper for at least 10 minutes.
While the tempeh marinates, prepare the quinoa according to package instructions if not already cooked.
Toss the broccoli florets with olive oil, salt, and pepper, then spread them out on a baking sheet.
Roast the broccoli in the preheated oven for 15-20 minutes until tender and slightly crispy on the edges.
Grill the tempeh slices for about 3-4 minutes per side until grill marks appear and the tempeh is heated through.
Plate the cooked quinoa, top with grilled tempeh slices, and arrange the roasted broccoli on the side.
Finish with an extra drizzle of lemon juice if desired and serve warm.