Testing - Fruit Vinegar

http://www.organicauthority.com/eco-chic-table/homemade-fruit-vinegar-recipe.html

For troubleshooting, also see:
http://www.rural-revolution.com/2013/07/making-fruit-scrap-vinegar.html
http://cooking.stackexchange.com/questions/51590/mold-on-vinegar-batch

2 cups any part of fruit including leftover peelings and cores (apple or pear peels and cores / any type of berry / tomato skins and seeds / plum, peach, apricot or nectarine skins any part of these fruits will work)
4 cups water
1 teaspoon organic white or brown sugar (optional for speeding up the fermentation process – will add extra flavor!)

1. Place your fruit scraps into a large (at least ½ gallon size), wide mouth mason or regular glass jar or a stone crock. Add the water and optional white or brown sugar. Cover the container with a muslin cloth to prevent dust, bugs or anything else falling into your vinegar solution. Place the container in a place where it can ferment undisturbed, preferably out of direct sunlight.
2. Let the fruit scraps and water sit for about 8 weeks, during which time a thick layer of goopy scum will form on the top. This scum, also known as the ‘mother’, is cellulose produced by acetic acid bacteria, which is ubiquitous in nature and present in all fermented, unpasteurized foods. The bacteria becomes present whenever ethanol is produced, which is what is happening when wild, airborne yeasts are feeding on the sugar in your fruit scraps.  Fruit flies carry acetic acid bacteria in their bodies, and so are actually an effective way to expedite vinegar making. If you want to allow fruit flies to help ferment your fruit scraps, keep your vinegar solution uncovered for about a day after beginning the process, check to see if any flies have landed, and cover the container with a cloth.
3. After the 8-week period, strain the liquid into a glass bottle through several layers of cheesecloth, a mesh bag or a fine mesh strainer, and cover with a metal cap or a cork stopper. After another 4 weeks, strain the liquid again through a clean cloth about the thickness of muslin into the bottle you want to store the vinegar in. Cap it, label it and you’ll have the fantastically fruity and tasty addition to your kitchen ingredients!

NOTE: A mother may re-develop in your finished vinegar, which will look a floating, gelatinous mass at the bottom of your bottle. Don’t throw this away! Much like a sourdough bread starter, it will kick-start future vinegar making processes, so save it in a small jar once you get to the end of your bottle.

Untested - Nectarine, Plum, and Apricot Upside-Down Cakes

http://www.marthastewart.com/353366/nectarine-plum-and-apricot-upside-down-cakes

For the Fruit Enhancer
 1 cup (2 sticks) unsalted butter, room temperature 
 3 tablespoons maple syrup 
 1 teaspoon dark rum 
 2 cups light-brown sugar, packed 
 1/2 teaspoon vanilla extract 
 1/2 teaspoon coarse salt 

For the Cake

 2 1/2 pounds nectarines, plums, or apricots, about 10 to 15 

 1 1/2 cups all-purpose flour, plus more for pans 

 1 1/2 cups cake flour, not self-rising 

 1 tablespoon baking powder 

 1 teaspoon salt 

 1 cup (2 sticks) unsalted butter, room temperature, plus more for pans 

 1 3/4 cups sugar, plus more for sprinkling fruit 

 4 large eggs 

 2 teaspoons pure vanilla extract 

 1 1/4 cups milk

1. Preheat oven to 350°F degrees. Make the fruit enhancer: In the bowl of a stand mixer fitted with the paddle attachment, combine the butter, maple syrup, dark rum, light-brown sugar, vanilla extract, and salt until well blended.
2. Spray five 6-by-3-inch round cake pans or three 12-cup standard muffin tins with cooking spray; if using cake pans, line the bottoms with parchment paper and spray with cooking spray. Divide fruit enhancer evenly among cake pans or muffin tins and spread with an offset spatula to make smooth.
3. Slice fruit into 1/4-inch wedges. Starting from the inside and working outwards, arrange fruit slices in a fanlike, circular pattern on top of fruit enhancer, using about 2 to 3 pieces fruit per cake. If making mini upside-down cakes, slice fruit into circular, cross-sectional slices about 1/4-inch thick, using one round slice per muffin tin. You can also use thin wedges or slices for the mini upside-down cakes, and arrange in a decorative fashion.
4. Make cake: Into a medium bowl, sift together flours, baking powder, and salt; set aside.
5. In the bowl of an electric mixer fitted with the paddle attachment, beat the butter and sugar until light and fluffy, 3 to 4 minutes, scraping down the sides of the bowl as needed. Beat in eggs, one at a time, and then beat in vanilla. With the mixer on low speed, add the flour mixture in three parts, alternating with the milk and beginning and ending with the flour; beat until combined after each addition.
6. Divide the batter between the prepared pans, and smooth with an offset spatula. Bake, rotating the pans halfway through, until the cakes are golden brown and a cake tester inserted in the centers comes out clean, 35 to 40 minutes for the 6-inch cakes, or 20 to 25 minutes for the mini upside-down cakes. Transfer pans to a wire rack to cool 30 minutes, or 20 minutes for minis. Loosen side of cake with small offset spatula or paring knife. Invert cakes onto a rack set atop a baking sheet; peel off the parchment if necessary. Serve warm or cool.