Pat the salmon cubes completely dry with paper towels to ensure a crisp, golden sear. Season evenly on all sides with kosher salt, black pepper, garlic powder, and smoked paprika.

Place a large heavy-bottomed cast iron skillet over medium-high heat. Add the olive oil and 1 tablespoon of butter, swirling until melted and shimmering hot.

Carefully place salmon cubes into the hot skillet in a single layer without overcrowding. Sear undisturbed for 2 to 3 minutes until a rich golden-brown crust forms on the bottom.

Gently flip each salmon bite using tongs. Sear the second side for another 1 to 2 minutes until cooked through to tender, flaky medium-rare perfection. Transfer bites to a warm plate.

Lower heat to medium. Add remaining 2 tablespoons butter, minced garlic, and lemon slices to skillet. Sauté for 60 seconds until fragrant. Pour in fresh lemon juice to deglaze, scraping up caramelized pan fond.

Return salmon bites to the skillet. Gently spoon bubbling lemon garlic butter glaze over each bite for 30 seconds. Remove from heat, garnish with fresh parsley, and serve immediately.