Enter interest from the IRS like a 1099Int and put the amount in box 1. Enter it manually and just enter IRS for the payer. Don't enter any other info like the address or a EIN. On the Let Us Enter Your 1099 page go down to the bottom and pick Enter a different way
Federal
Wages & Income
Interest and Dividends
Interest on 1099INT - Click the Start or Update button
Put the interest amount in box 1