Strawberry Apple Tarte Tatin - beautiful, delicious French dessert made with puff pastry. This tasty Caramel Apple Tart is made by caramelizing apples (and strawberries) first, and then baking them on top of puff pastry sheet.
Preheat the oven to 400 degrees Fahrenheit.
Peel and quarter the apples, toss the apple quarters in a large bowl with the lemon juice and 1/3 cup of the sugar. Set aside for 20 minutes to release the juices. In a separate bowl, toss strawberries with 2 tablespoons sugar, let them sit for 20 minutes as well.
Melt 6 tablespoons of butter in an oven-proof skillet. I used an All-Clad stainless steel pan (9 inches upper diameter across the top, 7 inches lower diameter across the bottom of the pan). Add 1 cup of sugar and 3-4 tablespoons of apple-lemon juices. Cook the mixture on medium-low heat, stirring constantly, for about 15 minutes, until mixture thickens, becomes smooth, and turns pale caramel color. In other words, when you transfer the spoon with the caramel mixture to the plate – the caramel coating the spoon should harden around the spoon almost immediately.
At this point, remove the skillet from the heat. Add apple quarters, arranging them rounded-side down in a decorative pattern in a circle along the side of the skillet. Top the apples with the remaining 2 tablespoons of butter, sliced. Cook the apples over medium-low heat for about 10 minutes, occasionally spooning the bubbling caramel liquid over them. You can also move apples around and then place them back in the same decorative pattern.
Add strawberries in the middle of the pattern and continue cooking both strawberries and apples for 15-20 more minutes on medium high heat, constantly stirring the liquid, pouring it over apples and strawberries, until the caramel sauce reduces and thickens. The sauce will be boiling with bubbles and should turn thick and of darker color. When you place some of that liquid on the spoon, it should be pretty thick and not runny. Remove the skillet from the heat, let the liquid stop bubbling. A thick dark (but not too dark) caramel sauce should be completely coating the apples and the strawberries. At this point, it’s ready to be placed in the oven. Apples should be slightly firm, not be too soft and the liquid should not turn dark brown.
Note: while you cook apples and strawberries in the sauce, strawberries especially produce a lot of liquid, so make the caramel sauce reduces to a thick consistency that’s not runny.
On a floured surface, roll the puff pastry sheet and cut out a circle about 10 inches in diameter, about 1/2 inch wider all around than the skillet. Make 4 cuts in the pastry for breathing during baking. Place the puff pastry circle over the apples and the strawberries in the skillet, tucking the overlapping portion down between the apples and the inside of the pan.
Place the skillet in the oven, and bake for about 30-35 minutes, until the pastry has puffed up, and is dry and golden brown. Remove the skillet from the oven, and let it to rest for a minute or two. Place a serving platter upside-down over the skillet and invert the tart onto the platter. Be very careful not to burn yourself as the skillet is very hot. Rearrange any apple slices that may have slipped or stuck to the skillet.