I have a spreadsheet:

A1 = "Year"
A2 down through A150 has values 1900 through 2050.

AB1 = "Thanksgiving"

I have written a custom function in a module called "Thanksgiving" and
it takes a year as the parameter.

If I'm in cell AB2, how can I call this function using the values in
AB1 and A2 to get the result. I know I can type in
=THANKSGIVING($AB$1, $A2) but I'd rather build the function call based
on the values already in my spreadsheet.

I've tried building a literal expression, but cannot get Excel to
evaluate it:

="="&AB1&"("&A2&")"

Any ideas? Thanks!