Lay thawed, shell-on shrimp on paper towels and blot both sides until no surface moisture remains; dry shells brown instead of steaming.
If you want the classic look but a cleaner bite, slip a paring knife under the shell ridge and lift out the vein without peeling.
Mix the dredge.
Whisk 2 Tbsp mochiko (or all-purpose) flour, 1 tsp sweet paprika, ¼ tsp cayenne and 1 tsp salt in a bowl.
Coat the shrimp & rest 5 min.
Toss shrimp until every shell is lightly dusted, then let them sit so the flour hydrates and won’t blow off in the pan.
Brown the garlic in butter first (3 min).
Melt 4 Tbsp butter over medium heat, add ¼ cup minced garlic and sauté until pale-gold and nutty, about 3 minutes.
Park the garlic-butter in a bowl.
Pour the sizzling butter-garlic out of the skillet; this prevents it from scorching during the shrimp sear.
Heat oil for a higher smoke point.
Add 1 Tbsp olive oil to the empty pan and crank to medium-high; the oil dilutes butter solids so the pan can reach searing temperature without burning.
Sear the shrimp in a single layer (2 min/side).
Drop shrimp in without crowding; cook 2 minutes until the underside turns pink, flip, and cook another 2 minutes—aim for a relaxed “C” shape, not a tight “O,” to avoid rubbery texture.
Work in two batches if needed so steam doesn’t build up.
Return the garlic-butter & baste (1 min).
Slide the reserved butter-garlic back in, toss to coat, and cook 60 seconds so the sauce clings to the shells.
Finish with lemon and parsley.
Off the heat, squeeze half a lemon over the pan and scatter 1 Tbsp minced parsley for color and brightness.
Plate North-Shore style.
Spoon shrimp and extra sauce onto a paper plate beside two scoops sticky rice and a scoop of macaroni salad; serve immediately while the shells are crisp.