For the breadcrumbs: Melt the butter in a large saute pan over medium heat. Add the anchovy paste and cook for 30 seconds. Add the garlic and cook for 1 minute.
Stir in the breadcrumbs and cook until lightly golden brown. Stir in the green onions, parsley and thyme and season with salt and pepper.
For the shrimp: Heat the oil in a large saute pan over medium heat until it begins to shimmer. Add the bacon and cook until golden brown and crispy, about 7 minutes. Remove the bacon with a slotted spoon to a plate lined with paper towels and reserve. Reserve the pan with the oil to cook the shrimp.
Whisk together the rice flour and 1 1/4 cups water in a large bowl and season with salt and pepper. Let rest for 5 minutes. Combine the cumin, ancho powder, chile de arbol, 2 teaspoons salt and 1/4 teaspoon pepper in a small bowl. Season the shrimp on both sides with the spice mixture.
Return the pan with the bacon fat to the burner and heat over high heat until it begins to shimmer. Dip the shrimp in the batter and let the excess drip off. Saute the shrimp in batches until lightly golden brown and just cooked through, 1 to 2 minutes per side.
For the grits: Put the hominy in a food processor with 1 cup of the cream and pulse until coarsely chopped.
Bring 2 cups of the shrimp stock to a simmer in a medium saucepan, add the hominy mixture and stir to combine. Cook until soft, about 5 minutes, adding more stock if needed. Add the Monterey Jack, Cheddar and the remaining cup of cream and cook until incorporated, about 2 minutes; season with the cayenne, salt and pepper.
Spoon the grits into bowls. Top each with 5 shrimp for an entree portion or 3 shrimp for an appetizer. Sprinkle with the breadcrumbs and garnish with the reserved bacon.