Italian Sausage Sub with Bourbon Mushrooms and Fennel Aioli
A hearty Italian-style sandwich featuring sweet sausage links paired with bourbon-glazed cremini mushrooms, slow-cooked caramelized onions, and sautéed bell peppers. The toasted fennel aioli adds an aromatic, Mediterranean touch that complements the rich flavors. Perfect for casual dinners or game day gatherings when you want something more substantial than typical sandwiches. The combination of sweet and savory elements, plus the melted provolone, creates a restaurant-quality sub you can make at home.
Ingredients
- 4 tablespoons extra virgin olive oil, divided
- ½ pound cremini mushrooms, sliced into thick slices
- 2 tablespoons bourbon
- 1 tablespoon butter
- 1 pound sweet onion, cut into 1/2 inch round half slices
- ¼ teaspoon black pepper
- 3 medium garlic cloves, sliced
- ⅛ cup fresh basil, chopped
- 1 tablespoon fennel seeds
- 1 teaspoon garlic, passed through garlic press
- ⅓ cup mayonnaise
- 1 pound Italian sweet sausage links
- 1 pound mixed sweet and mild peppers, cut into 1/2 inch wide strips
- ⅛ cup vermouth or white wine
- 3 8-inch sub or hoagie rolls, cut down side but left whole
- ¼ pound sliced provolone cheese, cut into 6 slices
Instructions
- 1
Heat large skillet on high with 1 tablespoon oil until smoking, add mushrooms and cook moving frequently to brown evenly
- 2
Turn off heat, add bourbon and stir until absorbed, transfer mushrooms to bowl
- 3
Heat pan to medium high, add 1 tablespoon oil and butter, add onions and black pepper
- 4
Reduce to medium low and cook 15 minutes stirring occasionally, add garlic and cook 10 more minutes
- 5
Turn off heat, stir in basil, transfer to bowl
- 6
Toast fennel seeds in small pan over medium high heat until lightly browned, crush to powder and mix with pressed garlic and mayonnaise
- 7
Heat large pan to medium high with 1 tablespoon oil, brown sausages 2 minutes per side
- 8
Reduce to medium and cook until cooked through, about 5-10 minutes, set aside
- 9
Remove all but 1 tablespoon fat, add remaining oil and heat to medium high
- 10
Add peppers and cook 15 minutes stirring occasionally until tender and browned
- 11
Heat to medium high, add vermouth and scrape pan bottom
- 12
Add all cooked ingredients, toss to combine and remove from heat
- 13
Heat oven to 350 degrees
- 14
Spread aioli inside cut rolls, add 2 sausages and vegetables to each
- 15
Top with 2 slices provolone per sub and bake until rolls are heated and cheese melts
Tips
Keep mushrooms on high heat to prevent them from releasing liquid and becoming soggy - this keeps them plump and well-browned.
Cook onions slowly on medium-low heat for proper caramelization - rushing this step will result in burnt rather than sweet onions.
Test sausage doneness by cutting one open if uncertain, as cooking times vary based on thickness and brand.
Good to Know
Refrigerate assembled subs wrapped in foil for up to 2 days, reheat in 350°F oven.
Cook all vegetables and sausage up to 1 day ahead, store separately and reheat when assembling.
Serve with chips and pickles as suggested, or with a simple green salad for a lighter accompaniment.
Common Mistakes
Don't cook mushrooms on medium heat or they'll release water and become soggy.
Avoid rushing the onion caramelization or they'll burn instead of sweetening.
Don't skip deglazing the pan as it captures all the flavorful browned bits.
Substitutions
Dairy-Free Swaps
General Alternatives
FAQ
Can I make the fennel aioli ahead of time?
Yes, the aioli can be made up to 3 days ahead and stored covered in the refrigerator. The flavors actually improve with time.
What if I can't find sweet Italian sausage?
You can use mild Italian sausage or even bratwurst. Avoid hot sausage as it may overpower the other flavors in the sandwich.
How long will leftover assembled subs keep?
Assembled subs keep 2 days refrigerated. For best texture, store components separately and assemble fresh when possible.