Prep the pan: Heat the oven to 350°F (175°C). Lightly grease a 12-cup muffin tin with cooking spray or butter. Make sure each cup is coated to prevent sticking.

Sauté the aromatics: Warm the olive oil or butter in a skillet over medium heat. Add the shallot and a pinch of salt. Cook 2–3 minutes, until softened, then stir in the garlic for 30 seconds.

Cook the kale: Add the chopped kale to the skillet. Cook, stirring, until wilted and tender, about 3–4 minutes. If the pan looks dry, add a teaspoon of water. Season lightly with salt and pepper. Remove from heat and let cool for a minute.

Whisk the eggs: In a large bowl, whisk the eggs, milk, 1/2 teaspoon salt, pepper, and smoked paprika or red pepper flakes if using. Whisk until the eggs look uniform and slightly frothy.

Add the cheese and kale: Stir in the cheddar and Parmesan, then fold in the cooled kale mixture. Taste a small drop for seasoning and adjust if needed.

Fill the tin: Divide the mixture evenly among the muffin cups, filling each about 3/4 full. Give the tin a gentle tap on the counter to release air bubbles.

Bake: Place on the middle rack and bake 14–18 minutes, until the centers are just set and no longer glossy. The tops will puff slightly and may pull away from the sides.

Cool and release: Let the frittatas sit in the pan for 3–5 minutes. Run a thin spatula or knife around the edges to lift them out. Serve warm or at room temperature.

Optional finishing touches: Top with a sprinkle of extra Parmesan, chopped herbs, or a tiny dollop of pesto or hot sauce.