It'll be tricky to plaster down to the work top, but not impossible.
I'd chisel or drill down at an angle as already suggested.
Tiling from work-surface up to about a foot above said surface, plasterwork needs to stop around 11" above work-surface, therefore.
@rodabod started
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It'll be tricky to plaster down to the work top, but not impossible.
I'd chisel or drill down at an angle as already suggested.