This tart is one of the best savory apple recipes since the buttery crust holds in a rich and flavorful caramelized onion layer, complemented by sharp cheddar cheese, and sweet apples.
Thinly slice the apples to ⅛ inch using a mandolin, toss them with a pinch of salt and 1 tablespoon of sugar. Coat the apples in a light squeeze of lemon. Let the apples sit in a colander over the sink or a bowl for an hour to help extract some moisture.
While the apples are sitting in the colander, add butter in a small saucepan over medium heat. Add the sliced onions and cook until lightly browned and they are starting to caramelize.
Meanwhile, roll out your store bought pie crust in a buttered tart pan. Pierce with a fork to prevent bubbles. Bake empty shell at 375 for 20 minutes
Stir together the caramelized onion, crème fraîche, mustard, thyme, salt and pepper. Spread evenly over the half baked pie crust. Top with cheddar cheese and bake for 10 minutes.
Arrange the apple slices on top in an overlapping circle. Bake the savory tart on the top oven rack until the pastry is golden and the cheese is melted, about 20 minutes.
Remove from the oven, brush the apples with melted butter and sprinkle with thyme, then cut into slices and serve.Enjoy!