BAKED SEA BASS:
Preheat the oven to 400 degrees F (204 degrees C).

In a small bowl, whisk together olive oil, lemon juice, and garlic powder.

Arrange sea bass fillets in a stoneware baking dish, with space between them. Use paper towels to pat them dry.

Brush the fish fillets on both sides with the olive oil mixture. Season both sides with garlic powder, sea salt, and black pepper.

Bake for 12-15 minutes, until the sea bass internal temperature reaches 135 to 140 degrees F, or the fish flakes easily with a fork. (For best results, use an instant-read thermometer — it's done when it reaches 135 to 140 degrees F.)

BEURRE BLANC:
Meanwhile, in a very small saucepan (about 5 inches in diameter) over medium-high heat, combine the shallot, wine, & vinegar. Bring to a boil, then reduce heat to medium and simmer for about 3-5 minutes, until the volume is reduced to about 1/4 of the original amount (approximately 2 tablespoons should be left).
Stir in the heavy cream and lemon zest.

Reduce heat to low. Add 2-3 cubes of very cold butter, stirring constantly until it melts. Continue to add butter 2-3 cubes at a time, stirring and letting it melt after each addition. Keep heat very low and avoid boiling, or the sauce will separate.

Season with sea salt to taste.

Serve sauce over baked sea bass immediately, or keep warm in a thermos or in the hot pan on the stove (with heat turned off) for up to 30-60 minutes. The sauce can split if it overheats or cools too much, so keep it warm but not hot.