Coarsely chop ¼ cup cashew nuts, and reserve for garnish. In the bowl of a food processor, combine 1 ¾ cups cashews with canola oil, and process until smooth, 5 to 7 minutes. (You should have about ¾ cup puree.) Set aside until completely cool.
In a medium mixing bowl, sift the flour and salt together; set aside.
In the bowl of an electric mixer fitted with the paddle attachment, combine the butter, cashew puree, and both sugars, and beat on medium speed until light and fluffy, about 2 minutes. Add the egg and vanilla, and mix until well combined, about 30 seconds. Add the flour mixture, and mix on low speed, just until combined, about 20 seconds. Wrap dough in plastic, and refrigerate at least 1 hour.
Preheat oven to 350 degrees. Line two baking sheets lined with parchment paper, and set aside. Scoop 2 tablespoons of dough and shape into a ball. Roll ball in Turbinado sugar. Place dough balls 3 inches apart on baking sheets. Press tines of a fork into the dough balls to make vertical and horizontal indentations. Sprinkle reserved cashew nuts on top.
Bake 16 to 18 minutes, depending on whether a soft or crisp cookie is desired. Transfer cookies to a wire rack to cool. Store in an airtight container at room temperature up to 1 week.