"you will need to make two journal entries:"

Actually, no, you don't need to make a JE at all. First, in payroll there is a provision for Benefits (taxable and nontaxable types) as "Company Contribution" so this can be "run through payroll" as part of allowing for Computation, even if it is not reported on the 940, 941, W2, etc. This is helpful when something is "based on wages" or Earnings.

"One increasing he IRA fund (set it up as a Banking account of type trust)"

You never track an IRA account in the Business data file; that IRA account is a Personal account owned by a Person. The Employer might be sending funds there, but that is not a Bank type of activity (asset accounting) for the Business entity.

"and decreasing the business checking account"

"And Decreasing Checking" = Write Check (entering an expense transaction). Now you can list the actual Payee, as well, because Banking menu has the banking tools. This would be instead of using payroll processing simply for computation, even as something set for Tax tracking as None. This would be, for instance, the employer paying out the Employer's optional contribution at year end, and they didn't want to compute anything relative to employee names throughout the year.

"(or recording the means of payment if not from business checking), and one journal entry debiting retirement plan expense and crediting retirement plan liability."

You don't need one JE, much less more of them.

If you use the "expense check" (even if ACH or EFT, and Paperless) to show the spending from Checking, you would list what you just paid out. You paid out Expense or you paid out Liability. And the way to Accrue that liability would be through payroll processing. And if you did that, you cannot treat that as a typical and regular "expense" entry; you would pay it out as any other tax-type liability.

So, it is always helpful to remind folks that you nearly never use JE in any QB product or program; and not for Banking; and not for something you computed through payroll. And not when Names are involved; paying out to brokerages = having a Payee name on the check expense or paying that from your liability tools from payroll, because you decided to compute it through payroll.

And often it is easier to wait until year end for the Employer Options, to see how much is available, or required to meet your Plan documents. For the Shareholder-employee, it often helps to wait until year end, because your Computed allowances takes into account your K-1 earnings and your W2 earnings. It's a bit more complicated, for you.