Spray a jelly roll pan with pan spray and line with parchment paper. Spray the parchment with pan spray and sprinkle 2-3 tablespoons of sugar over the parchment. Set the pan aside.
Whip the eggs on high speed until they are super light and fluffy, and what drips from the beaters holds its shape for 3 seconds. This is called the ribbon stage.
While the beaters are going, slowly add the sugar in a small stream.
Turn the mixer speed to low and add in the flour in three additions. Add the baking powder, salt, and xanthan gum.
Pour into prepared pan. Using a small offset spatula, gently rock the batter to the edges of the pan so that it's spread evenly to the corners. Be careful not to overwork the batter! The more gently you handle it, the more air bubbles you'll keep and the lighter and fluffier the cake will remain.
Bake for 7-8 minutes until a toothpick inserted in the center comes out clean.
Lay a large tea towel on a large, flat surface. Sometimes I double up the towels. Spread a piece of parchment over the towel.
When the cake is finished baking, gently run a palette knife or baby offset spatula around the edges to release it from the pan.
Sprinkle the top of the cake with a little bit of sugar to prevent it from sticking to the tea towel.
Invert the cake over the parchment-lined tea towel. Remove the parchment that you baked the cake on, and immediately roll the cake width-wise so it remains as long as possible.
Let the cake cool completely.
To make the Whipped Cream Filling
Add the heavy whipping cream, powdered sugar, and vanilla bean paste, and whip until medium peaks form.
To put it all together
When the cake is completely cool, gently unroll the tea towel and peel off the parchment paper.
Spread the whipped cream evenly over the top of the cake. Be gentle, so as to not rip the cake.
Starting with the part of the cake that is the most tightly rolled, spread the blueberries over the whipped cream. Concentrate them toward the part that will be the center of the roll.
Re-roll the cake (use the parchment to help, if needed, but be sure to peel it away from the cake).
Transfer the cake to a large platter and refrigerate until you're ready to serve it (at least 1 hour).
If your cake cracks, or you just want to dress it up a little bit, dust the top with a little bit of powdered sugar.