Melt butter; stir in pesto and garlic powder. Set aside.
Bread
In bowl of a stand mixer fitted with dough hook, stir together water, sugar, and yeast. Wait 5–10 minutes for it to foam (proof). Stir in oil, salt, Italian seasoning, and garlic.
Mix in white whole wheat flour and Parmesan cheese. Gradually add enough all-purpose flour until dough starts to pull away from sides of bowl. Knead 5 minutes.
Press dough into a greased 10-inch cast-iron skillet or 9-inch round baking pan. Cover; let rise 30 minutes.
Preheat oven to 400 degrees. Bake 20–23 minutes until golden brown. Remove bread from oven and immediately brush with topping. Cut in wedges and serve warm with remaining pesto-garlic butter topping.