First, lay out all the baguette slices in a single layer on a baking sheet, and broil for 4-5 minutes until lightly golden brown and toasted. Set aside while you prepare the toppings.

In a small bowl, smash the half avocado with the lime juice, salt, pepper, and a bit of garlic powder.

In a separate small bowl, combine the mascarpone cheese with the heavy cream, Italian herb seasoning, and some salt and pepper. Mix until smooth and creamy, adding more heavy cream if it's too thick.

Next, prepare the shrimp. In a small pan over medium-high heat, warm up the olive oil. Once hot, add in the shrimp, seasoning with salt, pepper, garlic powder, and some paprika. Cook until shrimp are pink and firm, and no trace of gray remains (about 5-6 min total). Set aside for now.

Now, prepare the mushrooms. Heat the olive oil in a small pan over medium-high heat. Add in the mushrooms, and season with salt, pepper, and garlic powder. Add in the parsley. Allow to cook until soft, 5-8 minutes. Add in the white wine and cook until evaporated, about 1-2 minutes more.

Finally, place half a slice of provolone on each of the 10 remaining crostini, and pop under the broiler for 2-3 minutes, until cheese is melted and bubbly. Top with half a slice of prosciutto each, and either serve immediately or return to the broiler for 1-2 more minutes to crisp up the prosciutto.

Assemble the other crostini as well. Spread the avocado on 10 crostini, and top each with a shrimp. Sprinkle some red pepper flakes and/or paprika on top. Spread the mascarpone on the remaining 10 of the crostini, topping each with some mushrooms and a little bit of parsley. Serve immediately!