Marinate the tofu “feta”: Crumble tofu into small pieces; toss with lemon juice, oregano, and pepper. Set aside.
Prep oven/pan: Preheat to 375°F (190°C). Lightly grease a standard 12-cup muffin tin with olive oil spray (or brush with 1 tsp oil). Heat 1 tbsp olive oil in a large non-stick skillet over medium heat.
Sauté aromatics: Cook onion and bell pepper 5–6 minutes until softened; add garlic 1 minute.
Dry spinach: Add squeezed spinach; cook, stirring, 2–3 minutes until very dry. Transfer mixture to a plate/bowl and cool 5–10 minutes.
Egg mixture: In a large bowl, whisk eggs, egg whites, paprika, baking powder, and optional salt vigorously for 1 minute until light and frothy.
Herbs & fiber: Whisk in parsley, dill, mint, and flaxseed to combine.
Combine: Fold in the cooled spinach mixture and the marinated tofu “feta” until just combined.
Bake: Divide batter among cups (¾ full). Bake 20–22 minutes, until centers are set and a skewer comes out clean or internal temp reaches ≥160°F (71°C).
Rest & release: Cool 5 minutes, loosen edges with a thin spatula, remove, and serve warm or cool completely for storage.