In a small saucepan, combine the apple cider vinegar, water, sugar, and salt. Bring to a simmer over medium heat, stirring until the sugar and salt are dissolved. Remove from heat.

Place the 1/2 cup of corn kernels in a heatproof bowl.

Pour the hot brine over the corn, ensuring the kernels are submerged.

Let sit at room temperature for at least 30 minutes, or refrigerate for longer. Drain well before using.

Heat a dry cast-iron skillet or heavy-bottomed pan over medium-high heat until very hot.

If using an ear of corn, char it directly in the hot pan, turning occasionally with tongs, until kernels are blackened in spots.

Let cool slightly, then cut off about 3/4 cup of the kernels.

If using frozen corn, add about 3/4 cup of the kernels directly to the hot pan and cook, stirring occasionally, until some kernels are blackened.

Set aside. Reserve the remaining 1 cup of fresh/frozen corn for the pudding base.

Roast the poblano pepper over an open flame (gas burner or grill) or under a broiler, turning occasionally, until the skin is blackened and blistered on all sides.

Place the roasted pepper in a bowl and cover it tightly with plastic wrap for 10-15 minutes to steam.

Remove the pepper from the bowl and peel off the blackened skin.

Remove the stem, seeds, and inner membranes. Dice the poblano.

Heat the olive oil in a skillet over medium heat.

Add the diced andouille sausage and cook, stirring occasionally, until browned and slightly crispy, about 5-7 minutes.

Remove the sausage from the skillet with a slotted spoon and set aside. Leave any rendered fat in the pan.

Preheat oven to 375°F (190°C). Grease an 8x8 inch baking dish or similar.

In the same skillet with the rendered sausage fat (add a little more olive oil if needed), add the remaining 1 cup of fresh/frozen corn kernels and cook for 3-5 minutes until slightly softened.

In a medium bowl, whisk together the milk, half-and-half, egg yolks, and flour until smooth. Stir in the sugar, baking powder, salt, and pepper.

In a clean, grease-free bowl, using an electric mixer, beat the egg whites until stiff, but not dry, peaks form.

This means the peaks hold their shape but are still slightly glossy.

In the prepared baking dish, combine the sautéed corn, blackened corn, pickled corn, diced roasted poblano, and cooked andouille sausage.

Stir gently to distribute the ingredients. Gently fold the egg yolk mixture into the corn and sausage mixture until just combined.

Carefully fold about one-third of the whipped egg whites into the corn mixture to lighten it. Use a rubber spatula or wooden spoon and a gentle folding motion to avoid deflating the whites.

Gently fold in the remaining egg whites until just combined and no white streaks remain.

Sprinkle the grated sharp cheddar and Gruyère cheese evenly over the top of the pudding.

Bake in the preheated oven for 40-50 minutes, or until the pudding is puffed up and lightly golden brown. The center should be mostly set (it might still have a slight jiggle).

Let the corn pudding rest for just a few minutes after removing it from the oven.

Soufflé-like dishes are best served promptly as they may deflate slightly.

Garnish with chopped fresh cilantro or green onions and serve warm.