Preparation

• Prepare seitan: Make TYBM’s vegan seitan beef according to the linked recipe up to the slicing step. You can make this a day or two ahead and refrigerate.
• Sauté veggies: Heat a large skillet over medium. Add the sliced onions and green pepper. Cook, stirring occasionally, 5–8 minutes until tender and edges show light char spots. If the pan dries and sticking begins, splash 1–2 tbsp water to deglaze or add a little oil. Stir in the minced garlic in the last 30–60 seconds. Remove the vegetables to a plate.
• Warm seitan: Increase heat to medium-high. In the same skillet, add the thinly sliced seitan and spread it into a single layer. Cook 2–3 minutes, turning once, until warmed through and the edges are slightly caramelized. Return the onions and peppers to the pan and toss to combine. Season with salt and freshly ground black pepper to taste.
• Make the cheese sauce: In a small saucepan over low–medium heat, melt 2 tbsp vegan butter. Sprinkle in 2 tbsp all-purpose flour and whisk constantly for about 1 minute to cook the flour. Slowly drizzle in ¼ cup almond milk while whisking to prevent lumps. When the mixture is smooth and starts to thicken, add the vegan provolone slices. Stir continuously until the slices melt into a glossy, cohesive sauce. If too thick, whisk in extra dairy-free milk 1 tbsp at a time until you reach the desired pourable consistency.
• Toast the hoagies: Brush the insides of the rolls with 1–2 tbsp melted vegan butter. Toast cut-side down in a hot skillet or place under the broiler 1–2 minutes until golden and crisp — watch closely to avoid burning.
• Assemble: Fill each hoagie with a generous pile of seitan, peppers, and onions. Spoon the provolone sauce over the filling, or tuck extra slices of vegan provolone into the warm mixture so they melt slightly. Serve immediately while hot.