Prep Mushrooms: Score the portobello caps in a shallow crosshatch pattern across the top, being careful not to cut all the way through to the gills.
Sear Mushrooms: In a large sauté pan over medium heat, melt the olive oil and butter together. Place the scored mushrooms, cut side down, in the pan. Cook for approximately two minutes.
Flip and Add Aromatics: Flip the mushrooms. Reduce the heat to medium-low and add the minced garlic and lemon slices to the pan.
Baste: Once the lemon slices begin to soften and stop "crackling" (sizzling aggressively), tilt the pan and use a spoon to baste the melted butter mixture over the mushrooms repeatedly.
Build the Sauce: Add the bouillon powder, white wine, lemon juice, capers, olives, brine, crushed red pepper flakes, and black pepper to the pan.
Simmer and Finish: Continue to baste the mushrooms with the sauce until they are tender and have fully absorbed the flavors of the piccata sauce.
Serve: Stir in the fresh parsley and season with salt to taste. Serve immediately, spooned over angel hair pasta, ensuring you toss the pasta in the remaining pan sauce.