Melt butter in the microwave; add brown sugar and lemon juice, stirring to dissolve sugar. Reserve 2/3°C.
Moisten a paper towel with cooking oil; using long-handled tongs, lightly coat the grill rack. Brush pork chops with remaining sauce. Grill, covered, over medium heat (you can also broil these 4" from heat), 4-5 minutes per side, or until a thermometer reads 145 degrees. Let stand 5 minutes before serving.
Stir reserved sauce to combine and gently rewarm if necessary; drizzle over the pork chops. Top with lemon slices, if desired.