Lovelace not showing 2 Decimals when last is zero


have a template sensor like this:

        value_template: '{{"{:.2f}".format(states("sensor.strom_tag_kosten") |float | round(2)) }}'
        unit_of_measurement: '€'

But in the Lovelace card only one decimal is shown, when second decimal is zero.
In the developer template editor it is shown correct, but not in Lovelace. Can anybody help?