Cut each grapefruit in half crosswise. Cut a thin slice off the bottom of each grapefruit half, if necessary, so that it will stand upright.
Using a silicone pastry brush, brush the top of the grapefruit halves with the Mazola® Corn Oil. Place the grapefruit halves upright on prepared sheet pans.
In a small bowl, stir together the brown sugar and cinnamon. Sprinkle the brown sugar mixture evenly over the grapefruit halves. Place the grapefruit halves under the preheated broiler, about 4 inches from the heat source, and broil for 2-3 minutes or until the sugar is bubbly.
Meanwhile, place ricotta cheese, honey, Greek yogurt and lemon juice in a small food processor or blender. Process until smooth and creamy, adding additional honey or Greek yogurt to reach desired taste and consistency.
When grapefruit are ready, serve immediately topped with 1-2 tablespoons of the whipped honey ricotta and 1 tablespoon chopped pistachios.