In bowl, whisk together flour, walnuts, baking powder. In another bowl, whisk together egg, buttermilk , butter and 2 tbsp syrup.
Stir flour mix into buttermilk mix until just combined. Let sit for 15 mins. Heat oven to 250. Melt 1 tbsp butter in lg skillet over medium heat. Add apple slices. Sprinkle w/ allspice and nutmeg. Cook 1 min, stirring. Add 3 tbsp maple syrup. Cook 2 mins, stirring until apples look glazed. Remove from heat.
Heat another lg skillet over medium heat. Brush pan lightly w/ canola oil. Add 1/4 cup pancake batter to pan. Place about 3 slices of apple mix on top of pancake. Gently press apllesa into pancake. Cook until bubbles form, flip over and cook until light brown. Repeat w/ reamining batter and apples. Keep pancake warm in oven until ready to serve.