Onion Tart, Caramelized

Preheat oven to 400 and remove puff pastry from freezer. Melt butter in large saute pan over med. heat. Add sliced onions and season w salt. Cook, stirring, until onions caramelize but retain some bite, about 15 min. Meanwhile, heat oil in a small pot over med. heat. Add minced onions and saute until softened but not browned, about 3 min. Add all but 1 T cream and bring to a boil. Reduce heat and simmer gently until onions are tender and cream tastes of onions, 5 min. Use a blender or food processor to puree until smooth. Season w salt. Line two baking sheets with parchment and place 1 sheet of pastry on each. Mix yolk w remaining cream and brush mix lightly over pastry. Bake until puffy and lightly golden, about 10 min. Spoon 3/4 of onion puree evenly over both sheets of pastry, leaving 1/2″ border all around. Spread caramelized onions over puree. Bake until topping gently sets and dough is deep golden at the edges, 12-15 min. Before serving, drizzle more puree over and garnish w chives.

Butter 4 T
Onions 1.5 large yellow onions, thinly sliced plus 1/2 oonion, minced
Olive oil 1 T
Heavy cream 1/2 c plus 1T
Frozen puff pastry 2 sheets
Egg yolk 1 beaten
Chives 3 T minced