You are looking for 406.5(G)
(G) Receptacle Orientation. Receptacles shall not be installed
in a face-up position in or on countertop surfaces or work
surfaces unless listed for countertop or work surface applica‐
tions
The 23 has changed the rules on peninsulas and other kitchen countertops in general if backsplash mounting isn't possible.. They will no longer count one below the counter top in the required receptacles. You will need a tombstone or listed pop up.
(article in EC&M magazine this month)
