Left: Phase coverage of the observations used in this work. The solid inner circle shows the stellar surface, while the middle and outer circles show the orbits of TOI-1518 b and TOI-1431 b, respectively, to scale. The observer is off the bottom of the page, and the vertical dashed lines show the line of sight, such that transit occurs in the lower intersection of the dashed lines and planetary orbits, and the secondary eclipse in the upper intersection. The planets orbit counter-clockwise. The colored points show the portions of the orbit where we obtained data. Right: signal-to-noise ratio of our observations as a function of orbital phase. The PEPSI red and blue arms are shown as the solid and dotted lines, respectively. The SNR values shown are, for each spectrum, the 95th quantile per-pixel signal-to-noise ratios.