Bayer Leverkusen’s 1-0 home win over Mainz on Tuesday had drawn Xabi Alonso’s defending champions within one point, but Bayern had no mercy against a listless Hoffenheim.
Former Manchester City winger Sane, who is looking to impress with his contract expiring in the summer, put the hosts in front six minutes in after a clever exchange of passes with veteran Thomas Mueller.
Harry Kane created Raphael Guerreiro’s 12th-minute goal, threading a pass to the Portuguese, who beat Hoffenheim and Germany goalie Oliver Baumann.
Kane contributed to the onslaught midway through the opening half, converting from the spot after a handball in the box.
The England captain has now converted 27 straight penalties for club and country, dating back to his miss against France in the World Cup quarter-finals in Qatar in 2022.
Sane got his second three minutes after half-time, tapping in a Mathys Tel cross from close range amid a more poor Hoffenheim defense.
Serge Gnabry got on the scoresheet after 66 minutes to bring up Bayern’s fifth, his first league goal since September.
Bayern leads the Bundesliga summit with four points clear of second place Bayer Leverkusen.
Elsewhere, Stuttgart came from a goal down at home to win 2-1 against RB Leipzig, who finished with nine men.
Benjamin Sesko gave Leipzig the lead after just 10 minutes, sliding in a Xavi Simons assist to score for the fifth league game in a row.
Five minutes into the second half, a superb long Deniz Undav cross found an unmarked Jacob Bruun Larsen, who headed Stuttgart level.
Undav created another 10 minutes later, pushing Leipzig into a desperation clearance only for Nick Woltemade to hammer home, taking Stuttgart up to fifth, a point behind the Saxons in the table.
Tempers boiled over for the visitors late, with both Sesko and fellow forward Lois Openda picking up second yellow cards.
In the German capital, Union Berlin’s poor run continued with a 2-0 loss to Augsburg.
Alexis Claude Maurice’s two first-half goals condemned Union, who last won in October, to a third league defeat in a row.
Heidenheim’s Leo Scienza covered a free kick in the fifth minute of stoppage time to salvage a 3-3 draw for his side at Werder Bremen.
