Beat butter in the bowl of a stand mixer fitted with the paddle attachment until soft. Beat in 1 cup sugar gradually until mixture is very light and creamy. Beat in sour cream, eggs, and 1 egg yolk. Stir in flour until dough comes together. Stir in baking powder, cinnamon, and lemon zest.
Divide dough in half; place each half on a sheet of plastic wrap. Shape each half into a 6-inch log of even thickness. Wrap tightly and refrigerate, 4 hours to overnight.
Preheat oven to 375 degrees F (190 degrees C). Grease 2 baking sheets.
Place dough on a flat work surface and let warm up slightly, about 10 minutes. Cut each log into 13 equal sections.
Roll sections back and forth with your fingers to create 10-inch ropes. Form each rope into a circle; overlap the left end over the right, twisting once, and press into a pretzel shape. Transfer pretzel cookies to the prepared baking sheets.
Whisk remaining egg yolk in a small bowl; brush over cookies. Sprinkle almonds and 1 tablespoon sugar on top.
Bake in the preheated oven until edges are dry, 10 to 15 minutes. Cool on the baking sheets for 5 minutes. Transfer to a wire rack to cool.