Directions:
Step 1: Pre-Salt the Eggplant
Cut the eggplant into 1/4-inch rounds, peeling the skin first if it feels thick.
Generously sprinkle kosher salt over both sides of the slices.
Let the slices sit in a single layer on paper towels for 20 to 30 minutes to sweat.
Step 2: Blend the Spinach Pesto
Add the spinach, basil, garlic, nuts, and a pinch of black pepper to a food processor.
Pulse the mixture while slowly drizzling in the olive oil until smooth.
Add the Parmesan cheese and pulse 2 to 3 times just to incorporate.
Taste, add a pinch of salt if needed, and set the pesto aside.
Step 3: Prep and Sauté the Mushrooms
Wipe off the tops of the mushroom caps using a clean, damp paper towel.
Snap or cut off the stems and gently scrape out the dark inner gills using a spoon.
Slice the remaining mushroom caps into 1/4-inch thick strips.
Heat 1 tablespoon of olive oil in a skillet over medium heat and add the Portobello strips once hot.
Season with a few pinches of salt and cook, stirring often, for 5 to 7 minutes until golden brown.
Season with black pepper, transfer to a plate, and set aside.
Step 4: Bread the Eggplant
Rinse the sweated eggplant slices quickly under cold water to remove excess salt.
Thoroughly blot the slices completely dry with paper towels.
Set out three wide, shallow bowls in a row containing all-purpose flour in the first, beaten eggs in the second, and Panko breadcrumbs mixed with smoked paprika in the third.
Dip each dry eggplant slice into the flour, then into the egg, and finally press firmly into the Panko mixture until fully coated.
Place the breaded slices on a wire rack until ready to fry.
Step 5: Pan-Fry the Eggplant
Add about 1/8 inch of frying oil to a large skillet over medium-high heat.
Test the oil by dropping a few Panko crumbs into it to ensure they sizzle instantly.
Add the eggplant slices to the hot oil in batches to avoid overcrowding the pan.
Fry for 3 to 4 minutes until the bottom is deeply golden brown and crispy.
Flip the slices over and fry the other side for another 2 to 3 minutes until fork-tender.
Transfer the fried eggplant immediately to a wire rack or paper-towel-lined plate.
Taste a small piece first, then lightly sprinkle with salt if needed.
Step 6: Assemble the Sandwiches
Toast your sandwich rolls if desired, then slice them in half lengthwise.
Spread a thick layer of Mascarpone cheese on the bottom half of each roll.
Spoon a generous layer of spinach pesto directly on top of the Mascarpone.
Layer 2 to 3 crispy fried eggplant slices over the pesto.
Top the eggplant with a handful of the sautéed Portobello mushroom strips.
Close the sandwich with the top roll and serve immediately while hot.