Preheat your oven to 350°F and grease a 9x13-inch baking dish generously with butter. I always coat the corners extra well because burnt edges happen fast at this temperature, and prevention beats scrubbing later.

Combine softened butter, milk, and eggs in a large bowl and whisk until no streaks of yolk remain. This emulsion step matters because it distributes butter evenly throughout the batter—skip it and you'll have greasy pockets that won't cook through properly.

In a separate bowl, whisk together flour, sugar, baking powder, and salt before folding into the wet mixture gently with a rubber spatula. Overmixing at this stage develops gluten, which makes the corn casserole Thanksgiving crowd sharing recipe dense instead of tender, so stop as soon as streaks disappear.

Fold in both the drained whole kernel corn and creamed corn, then stir in cheddar cheese and green onions until just combined. The green onions stay fresher when added last because they don't sit in the batter long enough to leach color or flavor.

Pour the batter into your prepared baking dish and smooth the top with an offset spatula. The surface should look slightly bumpy from corn kernels showing through—that's exactly what you want because it means proper distribution.

Drizzle the 2 tbsp of melted butter across the top in thin lines, then bake for 50 minutes until a knife inserted in the center comes out clean. I check at the 45-minute mark because every oven runs differently, and there's nothing worse than overbaked crowd corn casserole that's lost its tender texture.

Remove from the oven and let rest for 5 minutes before serving—this resting period lets the structure set so it holds together when you scoop it onto plates instead of collapsing into mush.