Toss together first 3 ingredients in a large bowl.
Melt butter in a large skillet over medium-high heat. Add nectarine mixture to skillet; bring to a boil, and cook, stirring often, 5 minutes. Spoon hot nectarine mixture into a lightly greased 13- x 9-inch baking dish. Spoon Blueberry Muffin Batter evenly over hot nectarine mixture.
Bake at 400° for 25 minutes or until crust is golden brown. Serve with vanilla ice cream.
*3 (21-ounce) cans peach pie filling can be substituted for nectarines. Omit sugar and flour. Melt butter in a large skillet over medium-high heat. Add peach pie filling, and bring to a boil; remove from heat. Proceed with recipe as directed.
Okay...first I must qualify my 4 star rating; it is based on the fact that I added cinnamon to the nectarines and then had Breyer's Slow Churned Vanilla Bean ice cream when served. Also, I cooked the recipe at a location over 7,000 ft. and didn't make any adjustments to the recipe for elevation. In spite of the elevation, the blueberry muffin actually cooked up quite well after adding an additional 10 minutes for browning.
I used fresh blueberries and very ripe (very ripe) nectarines. I love the flavors of the blueberries and nectarines together and will probably make this recipe again.
I wasn't a big fan of the outcome of this reipe. Pretty easy to make though. My husband and neighbor LOVED it though (probably would have given it four stars). I used fresh peaches and wanted to use blackberries, but they went bad while I wasn't looking so I used some frozen blueberries. I thought it was okay, but the other two loved it!