Pat tofu dry with kitchen paper. Cut into slices of 2 cm, and then cut diagonally into triangles. Mix soy sauce, mustard, garlic powder, maple syrup and 1 tsp of olive oil into a marinade. Let the tofu marinate for at least 15 minutes, ideally overnight.
Preheat oven to 220 °C upper/lower heat. Dip tofu in yeast flakes and distribute on a baking sheet lined with baking parchment. Slice potatoes in half. Combine with 1½ tbsp of olive oil, 1 tsp of salt, thyme, and polenta, and add to the baking sheet. Cut the lemon into slices of 5 mm and distribute over the tofu. Roast for 20 minutes.
Wash the asparagus. Combine with 1 tbsp of olive oil and ½ tsp of salt. Add to the baking sheet. Move the lemon slices onto the asparagus and continue roasting for another 20 minutes.
