In a large skillet, heat the olive oil over medium-low heat. Cook the smashed garlic until golden, about 5 minutes. Using a slotted spoon, transfer the garlic to a food processor; reserve the olive oil.
Add the parsley to the garlic in the food processor and pulse to finely chop; set aside 1/4 cup. Add the ricotta and parmesan to the food processor; pulse to combine.
Preheat the oven to 500 degrees . In the same skillet, heat the reserved olive oil over medium-high heat. Add the chopped garlic and cook, stirring, for 1 minute. Add the shrimp, season with salt and pepper and cook, stirring, until opaque, about 5 minutes. Stir in the reserved 1/4 cup parsley-garlic mixture.
Spread the cheese mixture on the cut side of each piece of bread and arrange on a parchment-paper-lined baking sheet. Spoon the shrimp mixture on top and sprinkle with more parmesan. Bake until the cheese is melted, 7 to 10 minutes.