(1 gallon/3.8 L, scale as needed)
OG = 1.068  FG = ~1.010 
ABV = ~7.6%

Ingredients

0.9 gallon (3.4 L) pasteurized pear juice
0.1 gallon (380 mL) pasteurized apple juice (the lower pH, the better)
Brown sugar to hit desired original gravity
1⁄4 tsp. Fermaid O or other yeast nutrient
Potassium metabisulfite (KMBS) powder
5 g Lalvin D47 yeast (or similar strain)
1⁄4 tsp. malic acid mixed in half cup of boiled water
30 g corn sugar (if priming)

Step by Step

Mix the pear juice, apple juice, malic acid solution, and brown sugar together until the sugar is fully dissolved. Note that the amount of brown sugar needed is dependent on the sugar content of the pear and apple juices used. Start small and measure after stirring the brown sugar until it is dissolved. Once you reach the desired original gravity, add yeast and seal fermentation vessel with airlock. Add yeast nutrient between 24 and 48 hours later.

Ferment until specific gravity reaches about 1.010, then cold crash and rack into a fresh container. Once the perry has dropped clear and fermentation has ceased, stabilize with ~50 g/L sulfite. Rack into a small keg and force carbonate or stir in priming sugar. You can also stir in the priming sugar (dissolved in a bit of hot water) and then rack to beer bottles and cap to carbonate, which will take a week or two. Keep refrigerated once carbonated.