Take out a cookie sheet and place 2 pieces of wax paper or plastic wrap the length of the cookie near the cookie sheet and set aside.
Place both sugars in a large mixing bowl.
In a small saucepan, melt butter and lard/shortening over low heat. Once melted, pour over sugar.
With the mixer running on low, mix until all sugar is moistened and there are no dry granules in the bowl.
Add the eggs and mix well.
With the mixer running, add baking soda, followed by cinnamon and mix well.
Turn off the mixer and add the flour. Mix just until you no longer see flour.
Add the slivered almonds and mix until almonds are evenly distributed.
Divide the dough between the two sheets of wax paper and form in rectangles about 2 inches tall and 3 inches wide. Wrap in wax paper and transfer to the refrigerator on cookie sheet. Let rest in refrigerator at least 8 hours or overnight.
Preheat oven to 350 degrees F.
Unwrap the cookie logs and slice 1/4 to 1/2 inch thick. Thicker slices will produce softer cookies but will take longer in the oven.
Place cookies at least 1 inch apart.
Bake in preheated oven for 8 to 10 minutes or until edges are beginning to brown and tops no longer look wet.
Remove from cookie sheet and place on cooling rack to finish cooling.
Prep Time includes an 8-hour rest in the refrigerator.Adapted from Allrecipes.