Preheat oven to 350°F. Grease standard muffin pans with butter, vegetable shortening, or cooking spray. 

Chop or dice apples coarsely, into ¼-inch pieces. 

In a large bowl whisk together flour, sugar, salt, baking soda, and cinnamon.

Stir in apples and nuts, coating them with flour mixture. Add oil, and mix vigorously with a large wooden spoon, until completely blended. Batter will be very stiff and chunky, like a dough. 

Scoop ⅓-cup of batter (a measuring cup works well for this) into your hands. Pat quickly into irregular balls, and place in prepared muffin pans. 

Bake at 350°F for 35 to 40 minutes, until muffins are golden brown with dry tops, and spring back when pressed gently.

Cool in pan for 5 to 10 minutes, then place on a cooling rack. Once completely cool, freeze, or store at room temperature in a sealed container for up to two days.

Source: California Walnut Board