Updated code:

package Logger;

use warnings;
use strict;

use Mojo::Log;

sub new {
    my $class = shift;
    my $self = {LogLine => '', appLog => Mojo::Log->new( path => './lo
+gs/mojo-log', level => 'debug' )};
    bless $self, $class;
    return $self;
}

sub add {
    my ( $self, $LogItem ) = @_;
    my $time = FormatDate();
    $self->{LogLine} .= "[ $time ] :: $LogItem\n" if defined($LogItem)
+;
    $self->{appLog}->debug($LogItem);
}

sub get {
    my( $self ) = @_;
    return $self->{LogLine};
}

sub clear {
    my( $self ) = @_;
    $self->{LogLine} = '';
}


sub FormatDate {
    my $Offset = shift; # number of seconds to offset the current time
+.  Example: FormatDate(3600) returns the time one hour from now.

    $Offset = 0 unless ($Offset);
    my ($Second, $Minute, $Hour, $Day, $Month, $Year, $WeekDay, $DayOf
+Year, $IsDST) = localtime(time+$Offset);
    $Year   = $Year + 1900;
    $Month  = $Month + 1;
    $Day    = sprintf ("%02s", $Day);
    $Month  = sprintf ("%02s", $Month);
    $Hour   = sprintf ("%02s", $Hour);
    $Minute = sprintf ("%02s", $Minute);
    $Second = sprintf ("%02s", $Second);
    return "$Year-$Month-$Day $Hour:$Minute:$Second";
}


1;
[download]

I decided to create a Mojo::Log object within my Logger class -- because I still want every call to Logger::add() to write to the Mojo log file as well. Creating a new instance of Mojo::Log inside the class seemed to work better than creating it in the main app and passing it in. Thanks again bliako for your suggestions.