Preheat oven to 350 degrees. Season tenderloin with salt, pepper and either ancho chile powder or paprika. Roast in oven until interior temperature reaches 145 degrees.
In the meantime make the gastrique. In a heavy bottomed pan, place sugar and water. Place over medium high heat, swirling pan to blend. As the sugar water mixture starts to cook, wet a pastry brush under the faucet and periodically wipe down sides of pan along the sugar line.
Cook sugar until it turns a golden brown. Remove from heat and add vinegar. The vinegar will harden the sugar. Place back on stove top and cook on medium for about 10 minutes. Swirling the pan to make sure the sugar remelts.
Once the mixture has started to thicken, remove from heat and add honey, basil and peach puree. Cook for another 15 minutes to thicken.
To serve, slice pork tenderloin and serve with a dollop of the peach gastrique.
This peach sauce would also be a great flavor for chicken.