Heat a 12-inch skillet over medium heat. Add 1 tablespoon butter and let it foam. Add the kielbasa slices in a single layer and cook undisturbed for 3-4 minutes until the bottoms are deeply browned and slightly crisp. Flip and cook another 2-3 minutes. Transfer to a plate, leaving the rendered fat in the pan.

In a bowl, whisk the eggs with heavy cream, garlic powder, and black pepper until just combined - do not over-beat or the eggs will get tough.

Add the remaining 1 tablespoon butter to the hot skillet over medium-low heat. Once melted, pour in the egg mixture. Let sit for 10 seconds until edges just begin to set, then gently fold with a spatula, scraping from the edges toward the center. Cook slowly, folding every 20-30 seconds, until eggs are softly set with some creamy curds remaining, about 4-5 minutes total. Remove from heat while still slightly underdone - they will finish cooking from residual heat.

Fold the browned kielbasa back into the eggs. Taste and adjust seasoning - the sausage is salty so you likely will not need salt. Transfer to warm plates immediately, sprinkle with fresh chives, and serve with hot sauce on the side if desired.