Put the frozen corn in a colander and rinse under cold running water until thawed, then drain very well. Finely grate the smoked Gouda, removing any wax or inedible rind. Set out a large deep skillet, about 12 inches wide.
Put the chopped bacon in the cold skillet. Cook over medium heat for 7–10 minutes, stirring occasionally, until browned and crisp. Transfer the bacon to a paper-towel-lined plate. Carefully pour the drippings into a heatproof container, then return exactly 1 tablespoon rendered bacon fat to the skillet; save or discard the rest separately. If your bacon yields less, use the available fat and stir carefully as the onion cooks.
Add the onion and cook over medium heat for 3–4 minutes until softened. Stir in the garlic and cook for 30 seconds. Sprinkle in the flour and stir constantly for 1 minute, coating the onion and scraping the pan without letting the flour scorch.
Slowly whisk in 1 cup milk, a little at a time at first, until no dry flour remains. Stir in the heavy cream, drained corn, and black pepper. Bring to a gentle simmer, then reduce the heat to medium-low. Cook for 5–7 minutes, stirring often, until the corn is hot and the sauce coats the kernels. Scrape the bottom to prevent sticking. Avoid a hard boil.
Remove the skillet from the heat. Add the smoked Gouda in small handfuls, stirring after each addition until melted and smooth. Fold in half the cooked bacon. Taste before adding any salt because the cheese and bacon already bring salt. If too thick, stir in 1–2 tablespoons additional milk.
Top with the remaining bacon just before serving so it stays crisp. Divide into 8 equal side-dish portions and serve hot. Refrigerate leftovers in shallow containers within 2 hours, or within 1 hour above 90°F.