Preheat oven to 375 degrees
Line jelly roll pan with waxed paper. Grease the wax paper and pan edges with shortening or spray with baking spray.
Dry ingredients: Sift together flour, baking powder, cinnamon and salt in a small bowl. Set aside.
In a large mixing bowl, beat the 3 eggs on high speed for 3 minutes.
Add sugar and beat on medium speed until fully incorporated.
Add cooked pumpkin and lemon juice and mix in on low speed until completely blended into the eggs and sugar.
Add dry ingredients into wet and mix in on low speed.
Spread cake mixture into prepared jelly roll pan. Make sure batter is evenly distributed in the pan.
Top with chopped pecans if using.
Place pan in oven and bake for 15 minutes.
Invert pan onto a clean dish towel sprinkled with powdered sugar. This step is crucial. Do it right when you take the cake from the oven and immediately proceed to the next step for best results.
Leave wax paper in place and gently roll the cake up in the towel carefully starting with the short side of the cake. Allow the cake to cool completely in the rolled towel so when it is time to add the filling it is already comfortable with the rolled up shape.