Peel, core, and chop the quince into quarters. In a heavy bottomed saucepan with a lid, combine quince, 4 tablespoons of butter and 0.5 cups of sugar. Cover and cook on medium low heat for 30-40 minutes, stirring periodically. The quince should be soft but not falling apart and darkened in color. Set to cool.

Place the pastry dough in a tart pan, crimp the edges as needed and freeze until ready to bake.

Peel, core, and quarter the apples. Use a sharp knife to slice the apples as thin as possible (I like to avoid mandoline injuries whenever possible!)

Slice the prepared quince as thinly as possible as well.

Preheat the oven to 375F. Take the pastry shell out of the freezer. Layer the quince slices evenly on the bottom of the tart. Follow by layering the apples over the quince - take more care with this part! - overlapping them to make full circles around the outer edge. Continue layering until you have made a small central circle with the apple slices (see photo).

In a small saucepan, brown the other 4 tablespoons of butter with the sprigs of rosemary. Butter should be foaming and smell nutty. Remove from heat, remove the rosemary and drizzle the brown butter over the apples.

Sprinkle remaining 0.25 cup of sugar over the top of the apples and bake for 70-80 minutes. Check to make sure that the apples are caramelized and the filling is nice and bubbling.

Allow tart to cool before serving. This is wonderful served a la mode!