Solved it:

Public Sub Marcus()
Dim a, toSub As Integer
Dim StartD As Date
Dim TodayD As Date

TodayD = FormatDateTime(Now, vbShortDate)
toSub = 2 - Weekday(TodayD)

StartD = FormatDateTime(DateAdd("d", toSub, TodayD), vbShortDate)

For a = 1 To 5
    Sheet1.Cells(a, 1) = FormatDateTime(DateAdd("d", a - 1, StartD))
Next a
End Sub