I have an Excel spreadsheet with a cell that I'd like to make, by
default, the size of two ordinary cells. I can insert a new row
underneath it and then merge that new row with the row I want to make
larger but if I do that the cell no longer resizes itself to
accommodate data.

Some of the existing rows are the size of two or so cells (in terms of
height) but, as right clicking on them and going to the Format
Cells... option on the resultant menu shows, they're not the result of
two merged cells - they're just one cell whose height has been
increased. And when you insert data, the cell resizes to accommodate
the data much an HTML element whose width or height have not been
explcitely specified.

That's what I'd like to do but I can't figure out how.

Any ideas?