01 -
Start by cooking down the applesauce in a medium saucepan over medium heat. Let it simmer and bubble away until it's reduced to about half the original amount - this usually takes around 10 minutes of stirring occasionally. You want it nice and thick! Set it aside in a bowl to cool completely.
02 -
Heat your oven to 350°F and line a couple of large baking sheets with parchment paper. This will keep your cookies from sticking and make cleanup a breeze.
03 -
In a big mixing bowl, whisk together the oats, flour, baking soda, salt, cinnamon, allspice, and nutmeg until everything's evenly distributed. Set this mixture aside for now.
04 -
Using either a hand mixer or stand mixer, beat the softened butter with both sugars until the mixture becomes light and fluffy - about 5 minutes of mixing should do it. Make sure to scrape down the bowl sides as you go.
05 -
Mix in your cooled, reduced applesauce, the egg yolk, and vanilla extract. Beat everything together until well combined, scraping the bowl as needed to get all those delicious bits incorporated.
06 -
Gradually add your dry ingredient mixture to the wet ingredients, mixing on low speed until just combined. Finally, fold in the diced apples and walnuts if you're using them. The dough will be thick and a bit sticky - that's perfect!
07 -
Using a medium cookie scoop or spoon, portion out the dough into mounds (about 1.5 tablespoons each) and place them 3 inches apart on your prepared baking sheets. Bake for 14-16 minutes until the edges are lightly golden and set, but the centers still look soft.
08 -
Let the cookies rest on the baking sheet for 10 minutes before transferring them to a wire rack. They'll finish setting up during this time and be perfectly chewy.
09 -
While cookies cool, melt the butter and maple syrup together in a small saucepan over low heat, whisking occasionally. Once melted, remove from heat and whisk in the powdered sugar until smooth. Taste and add a pinch of salt if desired.
10 -
Drizzle the warm glaze over the cooled cookies and let it set for about an hour. Store your finished cookies in an airtight container for up to 2 days at room temperature, or up to a week in the fridge.