Thoroughly coat all sides and bottom of the loaf pan with shortening and then a dusting of GF Flour. Set aside.
In a small microwave-proof bowl, melt the butter-substitute and set aside.
Using a Stand Mixer, with the Paddle attachment and set on Low, combine the GF Flour, Sugar, Salt and Yeast until completely blended.
In another microwave-proof bowl (or 2-cup glass measuring cup with a pour spout), heat the Oat Milk for 45-60 seconds or until just slightly warm.
Pour the melted Butter-substitute into the luke-warm Oat Milk and gently stir.
With the mixer on Low, slowly add the Milk mixture to the GF Flour Mixture until completely combined.
Scrape down the sides of the bowl and the paddle attachment. Increase the speed to Medium-High and beat for 5 minutes.
Using a rubber spatula, scrape the bread dough into the prepared loaf pan and spread evenly. Lightly spray the top with water and cover with plastic wrap (I spray one side of my plastic wrap with non-stick cooking spray, so it can be easily removed after the dough rises).
Place in a warm, draft-free spot to rise for about 1 - 1 1/2 hour (or more, depending on the current temperature) or until dough has risen slightly above the top of the pan.
Once the dough is ready to bake, place one oven rack in the lowest position and the other rack in the middle position of your oven. Next, place an oven-proof dish (I use a glass loaf pan) with about 1 Cup of water on the lower rack set off to one side, so as not to block the heat.
Preheat oven to 425 degrees.
Remove plastic covering from the bread loaf, sprinkle the top with the GF Whole Oats and bake for 35-40 minutes. Bread is done when it starts to pull away from the sides of the loaf pan and it makes a hollow thud sound when you gently thump it. Note: If the bread starts to get too dark on the top, cover loosely with foil (I start checking at the 15 minute mark).
Remove from oven and let cool in pan for about 10 minutes. Then, remove bread from the pan and continue cooling on a wire rack.
Enjoy with a buttery spread and honey or fresh jam/preserves...or slice to use for your favorite sandwiches :)