Combine and whisk together the all-purpose flour, whole wheat pastry flour, baking soda and salt in a medium bowl.
Outfit a stand mixer with the paddle attachment. Add the butter and sugar and cream together until light and fluffy, about 4 minutes, scraping down the sides of the bowl about halfway through beating. Beat in the vanilla and egg until blended. Beat in the flour mixture in three additions, scraping down the sides of the bowl to make sure everything is evenly mixed, and beat until combined. Add the oats, hazelnuts and toffee bits and mix until just combined. Cover the bowl with plastic wrap and refrigerate for 1 hour.
Preheat the oven to 350 degrees F. Spray two large baking sheets with nonstick cooking spray. Drop the dough by heaping tablespoons onto the baking sheets, leaving about two inches of space between each cookie. Bake until lightly golden brown all over, 15 to 18 minutes, rotating the baking sheets halfway through the baking.
Let cool on the baking sheets for 5 minutes. Transfer to a rack and cool completely. Store in an airtight container for up to 3 days.
Coconut palm sugar has an extremely low glycemic index and a high nutrient content, which makes it an amazing substitute for sugar. It has a slight caramel taste and gives your baked goods an almost "brown sugar" taste. Don't worry, it won't give your cookies a taste of coconut. I use half all-purpose and half whole wheat flour to give the cookies an extra bit of nutrition. And while these are no means a "healthy snack," they help ease some of the guilt of cookie season!