1. Preheat the oven to 190°C (375°F).
2. Mix together the flour, rolled oats, baking soda, and salt in a bowl.
3. Using an electric beater, beat the margarine, oil, brown sugar, egg, and vanilla in another bowl until mixture is well blended.
4. Add the dry ingredients to the wet ingredients and beat at low speed.
5. Add the surprise ingredients, except the jam, and mix well. For the jam option, top each cookie with about 1-2 mL (¼-½ tsp.) of jam before baking.
6. Place 12 small balls (about 30 mL/2 tbsp.) on each parchment-lined baking sheet. Flatten gently and bake on the middle rack for 10 to 12 minutes or until edges of cookies are golden brown. Let cool on baking sheet for 2 minutes before cooling completely on a wire rack. 

Surprises:
Add your choice of ingredients to the basic cookie dough recipe:

• 500 mL (1 cup) chocolate chips
• 125 mL (½ cup) chopped dried dates + 125 mL (½ cup) chopped nuts 
• 175 mL (¾ cup) dried cranberries + 125 mL (½ cup) coconut (reserve half the of coconut [60 mL or ¼ cup] to sprinkle over cookies before baking) 
• 30 mL (2 tbsp.) jam, the flavour of your choice