Answer the Sicilian with 2.c3 and d4: a big pawn centre, no long theory, and a calm game where you know the plans. This is a intermediate opening course for White (ECO B22), written for players rated around 1300. Each move is explained and then drilled on a board; it is free.
Key ideas of Alapin Sicilian (2.c3)
2.c3 prepares d4, so White keeps two pawns in the centre.
Against ...d5 the queen comes to d5 early: develop with tempo (Nf3, Be2, Nc3 later) and castle.
Against ...Nf6 push e5 and chase the knight; the extra space on the kingside is yours.
An isolated d-pawn after cxd4 is a strength in the middlegame: it supports pieces on e5 and c5.
The line trainer
The line trainer for Alapin Sicilian (2.c3) has 50 lines that grow out of 1. e4 c5 2. c3, learned a few new ones a day with spaced-repetition review.
chessGM