Step 1

Bring shallots, vinegar, butter, bourbon, maple syrup, ¼ tsp. salt, and 2 cups water to a boil in a large skillet over medium-high heat. Cover, reduce heat, and simmer, adding water by the tablespoonful if needed, until shallots are crisp-tender and liquid is partly evaporated, 25–30 minutes.

Step 2

Uncover shallots and cook until liquid is evaporated and shallots begin to brown, about 5 minutes. Continue to cook, swirling pan often, until shallots and surface of skillet are covered in a rich brown caramel, about 6 minutes. Add ¼ cup water to skillet and stir to deglaze caramel and coat shallots. Season with salt and pepper. Transfer to a microwave-safe bowl and let cool.

Step 3

To reheat, cover bowl with plastic wrap and microwave on high in 30-second intervals, tossing in between, until heated through, about 2 minutes. Taste and adjust seasoning with salt, pepper, and vinegar if needed.

Step 4

Do Ahead: Shallots can be made 1 day ahead. Cover and chill.