Preheat oven to 350 degrees. Line 3 baking sheets with parchment paper.
Combine the oil, maple syrup, molasses, vanilla and maple extracts, and sugar in a mixing bowl and stir until well combined. Add the milk and cornstarch and mix until the cornstarch is dissolved.
Add the flour and baking soda. Mix with a wooden spoon until well combined. Fold in the chopped walnuts.
Drop by tablespoonful about 2 inches apart onto the baking sheet. Press a walnut half into the center of each cookie. Bake for 8 to 10 minutes. Remove from oven, let sit 2 minutes, then transfer to a cooling rack.
Kay: I like walnuts a lot but I didn't like the walnuts on top. There's enough walnuts inside the cookie. My dad just said that there should be more walnut on top, though!
Mom (Dana): These are really sticky, chewy kind of cookies - my favorite kind! I had a lot of trouble getting the cornstarch to dissolve and ended up using my hands. Other than that, these were pretty easy and didn't require me to drag out my Kitchen Aid.