Preheat oven to 350 degrees F. Beat together butter and sugars with hand mixer or stand mixer fitted with paddle attachment for 3 minutes until light and fluffy.
Add egg and yolk and vanilla. Mix until combined and well incorporated.
Add flour, baking soda, and salt. Mix till just combined.
Fold in chocolate chips, walnuts, and butterscotch chips.
Bake in a 9x13 pan, or 6 tart pans and a loaf pan, 2 cake pans - get creative! Bake until lightly golden brown but do not overbake, you want these to bee gooey.
Option 1: Place egg whites and cream of tartar in a clean bowl. Whisk with whisk attachment of stand mixer or whisk by hand until soft peaks form. Slowly add the sugar as you keep whipping. Continue until stiff peaks form. Spoon on top of baked blondies. Bake for another 30 minutes at 250 degrees
Option 2: Place egg whites and sugar in bowl of a standmixer. Place over a simmering saucepan filled with 1 to 2 inches of water. Whisk continuously until sugar dissolves and mixture registers 160 degrees on an instant read thermometer. Remove from saucepan and whisk with standmixer for about 8 to 10 minutes until soft, thick, and glossy. Add vanilla. Spoon on top of blondies. Torch for that crispy brown look.