Preheat oven to 400°. In a large skillet, cook bacon over medium heat until crisp, stirring occasionally. Remove with a slotted spoon; drain on paper towels. Discard drippings, reserving 2 teaspoons in pan. Add onions, shallots and sugar to drippings; cook and stir over medium heat until vegetables are golden brown, 15-20 minutes.

Add wine, stirring to loosen browned bits from pan. Stir in thyme, garlic and pepper. Cook, uncovered, until liquid is evaporated, 2-3 minutes. Stir in bacon.

On a lightly floured surface, unfold puff pastry. Cut into three 9x3-in. rectangles. Transfer to a parchment-lined baking sheet. Brush dough with egg white; top with onion mixture and goat cheese. Bake until golden brown, 16-20 minutes. Cut each rectangle into 4 appetizers. Garnish with additional thyme if desired.