Preheat oven to 350 degrees. Spray a square or oblong baking dish with non-stick oil and set aside.
Put butter into a microwave safe container and microwave until. melted. Meanwhile, tear bread into small (about one-inch) pieces and place in prepared pan.
Crack eggs into a large mixing bowl and whisk until smooth. Mix in sugar, heavy cream, half and half, vanilla extract, and melted butter until uniform then stir in cinnamon, nutmeg, and sea salt.
Pour wet mixture over torn bread pieces and mix until each piece is coated and has soaked up the mixture (about 2 minutes). Transfer pan to oven to back for about an hour or until bread pudding is firm to the touch (but still springs back a bit) and golden brown. It should be slightly springy but not jiggly and will pull away from edges of pan a bit.
While bread pudding cools, sift powdered sugar into a bowl. Add in heavy cream and vanilla extract, and mix vigorously until smooth and uniform. Stir in pecans. Icing should be thin and glossy.
Pour glaze all over top of bread pudding. Alternatively, you can cut and glaze individual servings. Just be sure to do so while still warm.