Golden Beet, Tomato, Caramelized Onion, Goat Cheese Tarte Tatin

I realize the title of this is a mouthful.  I took out puff pastry and was going to make a pot pie but changed my mind and beet Tarte Tatin became the new plan.  I only had 2 beets though...so I put some onion in as well.  What I came up with:

• 397 grams puff pastry, thawed & rolled out to fit 10" non-stick pan
• Organic extra-virgin olive oil, as needed
• 1 tablespoon unsalted butter
• 1/2 pint organic grape tomatoes, halved
• 2 organic golden beets (1 lb), peeled, halved and sliced
• 2 onions, peeled, halved and sliced thinly
• 1 teaspoon fresh thyme leaves, stripped from stalk and more for garnish
• Fresh cracked pepper and kosher salt, to taste
• 1 tablespoon brown sugar
• 1 tablespoon balsamic vinegar
• 1/2 cup goat cheese, crumbled for garnish
• Balsamic glaze, for garnish

My dilemma at making this was do I sauté the onions and beets together?  Or onions first, beets next?  I have zero experience with raw beets so wasn't sure... In the end I decided to roast the beets the night before.  

I washed them, trimmed the ends off, rubbed them down with olive oil, wrapped them in foil and baked at 400°F for an hour on a baking sheet.  

I cooled and then peeled and sliced.  They were ready to be used this way without worry about proper cooking.  

I wanted to caramelize the onions first.  I used a non-stick skillet that was oven safe.  It's really a dream for desserts and pastry.  I put in a swirl of olive oil, butter, a bit of thyme and S&P.  When almost browned, I added in the tomatoes, beets, vinegar and brown sugar.  I stirred until all was warmed and incorporated.  I tried to arrange it so it would look pretty when it was flipped over.  

I preheated the oven to 425°F.  I rolled out the puff pastry to fit and then topped it over the veggies.  This went into the oven for 30 minutes.  It flipped fairly well, only a couple of things stuck and they were easy to remove.  

I garnished with the cheese, thyme and glaze.  

Other than being top heavy, it tasted delicious.  I was very happy with the results.  The goat cheese just took it over the top in flavor.  Great tang contrast to the sweet.