Preheat the oven to 350°F and spray a 9x13-inch cake pan with nonstick spray. Set aside.
In a large bowl, add the yellow cake mix, pumpkin puree, eggs, milk, vegetable oil, and pumpkin pie spice. Use an electric mixer to beat on medium speed for 2 minutes, until thoroughly combined.
1 box (15.25 oz) yellow cake mix, 1 can (15 oz) 100% pure pumpkin, 2 large eggs, ¾ cup whole milk, ¼ cup vegetable oil, 2 teaspoons pumpkin pie spice
Pour the pumpkin cake batter into the prepared pan. Bake for 30 to 35 minutes or until a toothpick inserted into the middle comes out clean, and the cake springs back when gently touched.
Remove the cake from the oven and let it cool for 10 minutes.
Use the end of a wooden spoon or a straw, to poke holes evenly all over the cake (only poke holes ¾ down into the cake, not all the way to the bottom), making sure to poke them in an even grid pattern (columns and rows) with about 1"-inch of space between each hole.
Pour the sweetened condensed milk and half of the caramel sauce over the cake, ensuring each hole is filled.
1 can (14 oz) sweetened condensed milk, 1 jar (12.25 oz) caramel sauce
Cover the cake with a lid or plastic wrap and refrigerate for at least 4 hours or up to overnight is even better (up to 24 hours).
Spread the Cool Whip over the cake and drizzle the cake with the remaining caramel sauce and toffee bits. Cut into squares and enjoy the cake chilled!
8 ounces Cool Whip, 1 cup English toffee bits