Use instead of a tab a shift-tab.
If you use it with some automatism, the shortcut is instead ^t or /t ^y or /y.
Tab leaders are difficult with right-indent tabs (Shift + Tab). You must either add another regular tqab beyond the frame edge and apply the leader to that, or use a dotted underline applied to the right indent tab, which I prefer.
That said, the advantage of the right-indent tab is it always aligns the following text to the right edge of the column, even if you later adjust the width, but there is nothing that would make it wrong to simply use a normal right-aligned tab with leader set to the right edge of the column. If all of your prices will have decimal values, you might want to use a Decimal-aligned tab instead.
Here's how I would approach it:
Type in the food item, followed by a single tab, followed by the price, press Enter/Return.
Select the text, Type > Tabs.
Click the Right-align tab in the tab well, click it above the ruler, towards the right side of the column.
Keep the tab selected (blue or orange background depending on the UI brightness). Add a period (I added a period and a space) in the Leader box. Press Enter.
Once the tab is formatted corrected, gently drag it to the right, and place it over the right indent triangle.
You might want to save it as a style to that future updates are easier.