Preheat oven to 450 degrees F (230 degrees C).
Toss the Red Potato (1.25 pound) with the Olive Oil (2 tablespoon), Salt (1/4 teaspoon), and Freshly Ground Black Pepper (1/4 teaspoon); arrange in single layer on rimmed baking sheet. Bake 20 to 25 minutes or until golden brown and tender. Rearrange potatoes halfway through to promote even browning.
When potatoes are done, reduce oven temperature to 375 degrees F (190 degrees C).
Meanwhile, whisk together the Egg (4) and Half and Half (1/4 cup) along with Salt (1/2 teaspoon); stir in the Gruyère Cheese (2 cup), Fresh Basil (1/4 cup), Fresh Parsley (1/4 cup), and Garlic (3 clove) in a large bowl.
Add the Fresh Spinach (3 cup) and Fennel Bulb (2) to the egg mixture and mix well. When ready, add the roasted potato chunks and toss until well incorporated. Transfer to a 2-quart baking dish; cover with foil.
Bake for 30-35 minutes or until custard has set.
Uncover; bake another 5 minutes. Garnish with additional basil and parsley, if desired. Enjoy!