Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
In a large bowl, toss the broccoli florets and chopped red bell pepper with 0.5 tablespoon of avocado oil, garlic powder, onion powder, sea salt, and black pepper.
Spread the vegetables in a single layer on the baking sheet and roast for 15-20 minutes until the edges are tender and slightly charred.
While the vegetables roast, slice the tempeh into 0.5-inch thick strips or triangles.
Heat the remaining 0.5 tablespoon of avocado oil in a non-stick skillet over medium-high heat.
Add the tempeh slices to the skillet and sear for 3-4 minutes per side until they develop a deep golden-brown crust.
Lower the heat to medium and pour the tamari and lemon juice over the tempeh, flipping the pieces to coat them evenly as the liquid reduces into a glaze.
Remove from heat and serve the glazed tempeh immediately alongside the roasted vegetables.