Preheat your oven to 375°F. While it heats, pour the Just Egg into a bowl and whisk together with the cream, black salt, and black pepper until fully combined and smooth. Set this mixture aside—this is your vegan egg base that will cook into the frittata.

Heat the olive oil in a 10-inch oven-safe skillet over medium heat. Add the diced onion and cook for 2-3 minutes until it begins to soften and turn translucent. Add the minced garlic and cook for 30 seconds until fragrant. Then add the sliced mushrooms and red bell pepper, stirring occasionally for 4-5 minutes until the mushrooms release their moisture and all vegetables are tender. I like to slice mushrooms thin so they soften evenly and don't remain chewy in the final frittata.

Add the spinach to the skillet and stir for about 1 minute until it wilts completely. This quick cook preserves the spinach's nutrients and prevents it from becoming mushy during the baking stage. Once wilted, the vegetables are ready to become the frittata filling.

Pour the Just Egg mixture from Step 1 directly over the cooked vegetables in the skillet, stirring gently to distribute the vegetables evenly throughout. Sprinkle the vegan cheese evenly over the top of the egg mixture. The cheese will melt slightly and create a nice golden top as it bakes.

Transfer the skillet to the preheated 375°F oven and bake for 15-20 minutes, until the frittata is set around the edges and slightly firm in the center when you gently shake the pan. The cooking time may vary depending on your oven, so start checking at 15 minutes. I find that a slight jiggle in the very center is ideal—it will continue to set slightly as it cools.

Remove the skillet from the oven and let the frittata cool for 5 minutes. This resting period allows the Just Egg to fully set and makes slicing cleaner. Slice into wedges directly in the skillet or slide onto a cutting board, and serve warm.